DSQ: Calculating whether quadrilaterals are similar - GMAT Quantitative
Card 1 of 72
What is the perimeter of Rhombus 
?
Statement 1: 
Statement 2: 
What is the perimeter of Rhombus
Statement 1:
Statement 2:
Tap to reveal answer
Each statement gives the length of one diagonal of the rhombus. Knowing one diagonal is not enough to give the perimeter of the rhombus.
Knowing the lengths of both diagonals, which is the case if both statements are assumed, is enough to determine the perimeter. The rhombus in question, along with its diagonals, is as shown below:
As marked in the diagram, the diagonals are perpendicular, and they are also are each other's bisector. It follows from the given lengths that 
and 
, so 
can be calculated using the Pythagorean Theorem. The perimeter is four times 
, since all sides of a rhombus are congruent.
Each statement gives the length of one diagonal of the rhombus. Knowing one diagonal is not enough to give the perimeter of the rhombus.
Knowing the lengths of both diagonals, which is the case if both statements are assumed, is enough to determine the perimeter. The rhombus in question, along with its diagonals, is as shown below:
As marked in the diagram, the diagonals are perpendicular, and they are also are each other's bisector. It follows from the given lengths that
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True or false: Rhombus 
Rhombus 
.
Statement 1: 
Statement 2: 
True or false: Rhombus
Statement 1:
Statement 2:
Tap to reveal answer
Assume Statement 1 alone. A rhombus being a parallelogram, its opposite angles and its adjacent angles are supplementary. From this fact and Statement 1 alone, it follows that
, 
, 
, and 
.
By definition of a rhombus, all of its sides are congruent. By substitution,
.
All side proportions hold as well as all angle congruences, so the similarity statement holds.
Assume Statement 2 alone. Construct the diagonals of the rhombuses, as follows:
In each rhombus, the diagonals are each other's perpendicular bisector. If
then
Since 
, both angles being right, it follows via the Side-Angle-Side Smiilarity Theorem that
,
and , by similarity,
.
By a similar argument,
,
and by angle addition,
.
As with Statement 1 alone, congruence of one set of corresponding angles in two rhombuses leads to the similarity of the two.
Assume Statement 1 alone. A rhombus being a parallelogram, its opposite angles and its adjacent angles are supplementary. From this fact and Statement 1 alone, it follows that
By definition of a rhombus, all of its sides are congruent. By substitution,
All side proportions hold as well as all angle congruences, so the similarity statement holds.
Assume Statement 2 alone. Construct the diagonals of the rhombuses, as follows:
In each rhombus, the diagonals are each other's perpendicular bisector. If
then
Since
and , by similarity,
By a similar argument,
and by angle addition,
As with Statement 1 alone, congruence of one set of corresponding angles in two rhombuses leads to the similarity of the two.
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Determine if rectangles 
and 
are similar.
I) 
has a perimeter of 16 units and side 
is 3 units long.
II) 
has area of 44 units and side 
is 6 units long.
Determine if rectangles
I)
II)
Tap to reveal answer
Similar rectangles (or any shape for that matter) are the same shape but can be different sizes. What that means is that their side lengths all follow a common ratio; if one pair of corresponding sides follow the ratio 2:1, then all corresponding sides must follow the same ratio.
Statement I gives us the perimeter and one side of 
.
Statement II gives us the area and one side of 
.
We can find all the sides of both rectangles, but we need both statements to do so. Once we have all side lengths, we can compare them to see if they follow the same ratios.
IF 
has perimeter of 16 and one side is 3, we can find the other side using the following:
If 
has area of 44 and side of 6, the other side can be found via the following:
Compare the ratios of the sides to find out whether the two rectangles are similar:
Therefore, the rectangles are not similar.
Similar rectangles (or any shape for that matter) are the same shape but can be different sizes. What that means is that their side lengths all follow a common ratio; if one pair of corresponding sides follow the ratio 2:1, then all corresponding sides must follow the same ratio.
Statement I gives us the perimeter and one side of
Statement II gives us the area and one side of
We can find all the sides of both rectangles, but we need both statements to do so. Once we have all side lengths, we can compare them to see if they follow the same ratios.
IF
If
Compare the ratios of the sides to find out whether the two rectangles are similar:
Therefore, the rectangles are not similar.
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True or false: Rhombus 
Rhombus 
.
Statement 1: 
and 
Statement 2: The area of Rhombus 
is 49 times that of Rhombus 
.
True or false: Rhombus
Statement 1:
Statement 2: The area of Rhombus
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that corresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary—that is, their angle measures total 
. Therefore, it is necessary and sufficient to prove just one pair of corresponding angles congruent.
The two statements together give no information about the measures of any of the angles of the rhombus. Therefore, together, they do not answer the question of whether they are similar or not.
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that corresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary—that is, their angle measures total
The two statements together give no information about the measures of any of the angles of the rhombus. Therefore, together, they do not answer the question of whether they are similar or not.
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True or false: Rhombus 
Rhombus 
.
Statement 1: 
and 
are both 
angles.
Statement 2: The area of Rhombus 
is four times that of Rhombus 
.
True or false: Rhombus
Statement 1:
Statement 2: The area of Rhombus
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that coresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary - that is, their angle measures total 
. Therefore, it is neccessary and sufficient to prove just one pair of corresponding angles congruent.
Assume Statement 1 alone. 
is a 
angle, so any angle consecutive to it, which includes 
, is supplementary to it—that is, the angle measures total 
. This makes 
a 
angle. Its corresponding angle in Rhombus 
is 
, which is a 
angle. Since 
and 
are noncongruent, it follows that Rhombus 
Rhombus 
. (Note that it can be demonstrated that the rhombuses are similar, but the correct statement is Rhombus 
Rhombus 
.)
Statement 2 alone provides no useful information; the relationship between the areas of the rhombuses is irrelevant.
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that coresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary - that is, their angle measures total
Assume Statement 1 alone.
Statement 2 alone provides no useful information; the relationship between the areas of the rhombuses is irrelevant.
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True or false: Rhombus 
Rhombus 
.
Statement 1: 
Statement 2: 
True or false: Rhombus
Statement 1:
Statement 2:
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that coresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary—that is, their angle measures total 
. Therefore, it is neccessary and sufficient to prove just one pair of corresponding angles congruent.
Assume Statement 1 alone. 
and 
are not corresponding angles, so their congruence does not prove the rhombuses are similar; however it does not prove they are not similar either; for example, two squares are both rhombuses with four right angles, so they are similar and fit this condition.
Assume Statement 2 alone. 
and 
are two angles of the same rhombus, so similarity cannot be proved or disproved without information about the other rhombus.
Now assume both statements. 
and 
are consecutive angles of Rhombus 
; a rhombus being a parallelogram, the degree measures of the angles total 
. From Statement 2, they are congruent, so each measures 
. Since 
from Statement 1, 
also measures 
. Since each parallelogram has at least one right angle, each has four right angles. Therefore, corresponding angles are congruent, so the rhombuses are similar.
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that coresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary—that is, their angle measures total
Assume Statement 1 alone.
Assume Statement 2 alone.
Now assume both statements.
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Isosceles Trapezoid 
has bases 
and 
.
Isosceles Trapezoid 
has bases 
and 
.
True or false:
Trapezoid 
Trapezoid 
Statement 1: 
and 
are both 
angles.
Statement 2: 
and 
Isosceles Trapezoid
Isosceles Trapezoid
True or false:
Trapezoid
Statement 1:
Statement 2:
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent and that their corresponding sides are in proportion.
We show that Statement 1 alone provides insufficient information by examining two cases.
Case 1: Trapezoid 
Trapezoid , with a angle.
A pair of base angles of an isosceles trapezoid are congruent, so, since 
measures 
, so does 
. The leg angles of a trapezoid have measures whose sum is 
, so 
and 
measure 
. By congruence of corresponding angles, 
, so measures 
, and the conditions of Statement 1 are met. Furthermore, two congruent triangles are also similar, so Trapezoid Trapezoid .
Case 2: Examine the figure below, in which 
. Note that these congruent upper bases have been superimposed upon each other:
The trapezoids are isosceles since their base angles are congruent; also, the conditions of Statement 1 are met. However, 
, but 
. The sides are not in proportion, so the trapezoids are not similar.
Assume Statement 2 alone. Two congruent trapezoids whose side lengths fit the conditions of the statement are also similar. But examine this diagram, in which 
, 
, and 
. Note that the congruent upper bases have been superimposed upon each other:
The conditions of Statement 2 are met, but 
, so the trapezoids are not similar.
Now assume both statements to be true. As stated before, it follows from Statement 1 that all corresponding angles are congruent. 
and 
, so it follows from the Division Property of Equality that
It remains to be demonstrated that 
is equal to the above ratios as well. If the diagonals 
and 
are constructed, 
and 
are formed; since 
and 
, by the Side-Angle-Side Similarity Theorem, 
. It follows that 
, and by angle addition, since 
, it follows that 
. From the Angle-Angle Postulate, the other two triangles formed are similar—that is, 
—and it follows that 
. Therefore, all four sides of the trapezoids are in proportion, and the trapezoids are similar.
To prove two figures similar, we must prove that their corresponding angles are congruent and that their corresponding sides are in proportion.
We show that Statement 1 alone provides insufficient information by examining two cases.
Case 1: Trapezoid
A pair of base angles of an isosceles trapezoid are congruent, so, since
Case 2: Examine the figure below, in which
The trapezoids are isosceles since their base angles are congruent; also, the conditions of Statement 1 are met. However,
Assume Statement 2 alone. Two congruent trapezoids whose side lengths fit the conditions of the statement are also similar. But examine this diagram, in which
The conditions of Statement 2 are met, but
Now assume both statements to be true. As stated before, it follows from Statement 1 that all corresponding angles are congruent.
It remains to be demonstrated that
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Isosceles Trapezoid 
has bases 
and 
.
Isosceles Trapezoid 
has bases 
and 
.
True or false:
Trapezoid 
Trapezoid 
Statement 1: 
Statement 2: 
Isosceles Trapezoid
Isosceles Trapezoid
True or false:
Trapezoid
Statement 1:
Statement 2:
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent and that their corresponding sides are in proportion.
Assume both statements are true. We show that they provide insufficient information by examining two scenarios.
Case 1: Trapezoid 
Trapezoid 
, then 
and 
, so the conditions of both statements are met; also, since the trapezoids are congruent, they are also similar.
Now examine isosceles trapezoid 
below, in which 
, 
, 
, and 
are positioned on the bases so that 
and 
.
Since 
and 
, Quadrilateral 
is a parallelogram, and 
; similarly, 
. Therefore, Trapezoid 
is also isosceles. Also, by the Corresponding Angles Theorem, 
and 
, and the conditions of both statements are met. However, corresponding sides are not in proportion, since 
, but 
; consequently, the trapezoids are not similar.
To prove two figures similar, we must prove that their corresponding angles are congruent and that their corresponding sides are in proportion.
Assume both statements are true. We show that they provide insufficient information by examining two scenarios.
Case 1: Trapezoid
Now examine isosceles trapezoid
Since
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Isosceles Trapezoid 
has bases 
and 
.
Isosceles Trapezoid 
has bases 
and 
.
True or false:
Trapezoid 
Trapezoid 
Statement 1: 
Statement 2: 
Isosceles Trapezoid
Isosceles Trapezoid
True or false:
Trapezoid
Statement 1:
Statement 2:
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
Assume both statements are true. We show that they provide insufficient information by examining two scenarios.
If Trapezoid 
Trapezoid 
, then 
and 
, so the conditions of both statements are met; also, since the trapezoids are congruent, they are also similar.
Now examine isosceles trapezoid 
below, in which 
, 
, 
, and 
are positioned on the bases so that 
and 
.
Since 
and 
, Quadrilateral 
is a parallelogram, and 
; similarly, 
. Therefore, Trapezoid 
is also isosceles, and the conditions of both statements are met. However, corresponding sides are not in proportion, since 
, but 
; consequently, the trapezoids are not similar.
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
Assume both statements are true. We show that they provide insufficient information by examining two scenarios.
If Trapezoid
Now examine isosceles trapezoid
Since
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What is the perimeter of Rhombus ?
Statement 1:
Statement 2:
What is the perimeter of Rhombus
Statement 1:
Statement 2:
Tap to reveal answer
Each statement gives the length of one diagonal of the rhombus. Knowing one diagonal is not enough to give the perimeter of the rhombus.
Knowing the lengths of both diagonals, which is the case if both statements are assumed, is enough to determine the perimeter. The rhombus in question, along with its diagonals, is as shown below:
As marked in the diagram, the diagonals are perpendicular, and they are also are each other's bisector. It follows from the given lengths that and , so can be calculated using the Pythagorean Theorem. The perimeter is four times , since all sides of a rhombus are congruent.
Each statement gives the length of one diagonal of the rhombus. Knowing one diagonal is not enough to give the perimeter of the rhombus.
Knowing the lengths of both diagonals, which is the case if both statements are assumed, is enough to determine the perimeter. The rhombus in question, along with its diagonals, is as shown below:
As marked in the diagram, the diagonals are perpendicular, and they are also are each other's bisector. It follows from the given lengths that
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True or false: Rhombus Rhombus .
Statement 1:
Statement 2:
True or false: Rhombus
Statement 1:
Statement 2:
Tap to reveal answer
Assume Statement 1 alone. A rhombus being a parallelogram, its opposite angles and its adjacent angles are supplementary. From this fact and Statement 1 alone, it follows that
, , , and .
By definition of a rhombus, all of its sides are congruent. By substitution,
.
All side proportions hold as well as all angle congruences, so the similarity statement holds.
Assume Statement 2 alone. Construct the diagonals of the rhombuses, as follows:
In each rhombus, the diagonals are each other's perpendicular bisector. If
then
Since , both angles being right, it follows via the Side-Angle-Side Smiilarity Theorem that
,
and , by similarity,
.
By a similar argument,
,
and by angle addition,
.
As with Statement 1 alone, congruence of one set of corresponding angles in two rhombuses leads to the similarity of the two.
Assume Statement 1 alone. A rhombus being a parallelogram, its opposite angles and its adjacent angles are supplementary. From this fact and Statement 1 alone, it follows that
By definition of a rhombus, all of its sides are congruent. By substitution,
All side proportions hold as well as all angle congruences, so the similarity statement holds.
Assume Statement 2 alone. Construct the diagonals of the rhombuses, as follows:
In each rhombus, the diagonals are each other's perpendicular bisector. If
then
Since
and , by similarity,
By a similar argument,
and by angle addition,
As with Statement 1 alone, congruence of one set of corresponding angles in two rhombuses leads to the similarity of the two.
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Determine if rectangles and are similar.
I) has a perimeter of 16 units and side is 3 units long.
II) has area of 44 units and side is 6 units long.
Determine if rectangles
I)
II)
Tap to reveal answer
Similar rectangles (or any shape for that matter) are the same shape but can be different sizes. What that means is that their side lengths all follow a common ratio; if one pair of corresponding sides follow the ratio 2:1, then all corresponding sides must follow the same ratio.
Statement I gives us the perimeter and one side of .
Statement II gives us the area and one side of .
We can find all the sides of both rectangles, but we need both statements to do so. Once we have all side lengths, we can compare them to see if they follow the same ratios.
IF has perimeter of 16 and one side is 3, we can find the other side using the following:
If has area of 44 and side of 6, the other side can be found via the following:
Compare the ratios of the sides to find out whether the two rectangles are similar:
Therefore, the rectangles are not similar.
Similar rectangles (or any shape for that matter) are the same shape but can be different sizes. What that means is that their side lengths all follow a common ratio; if one pair of corresponding sides follow the ratio 2:1, then all corresponding sides must follow the same ratio.
Statement I gives us the perimeter and one side of
Statement II gives us the area and one side of
We can find all the sides of both rectangles, but we need both statements to do so. Once we have all side lengths, we can compare them to see if they follow the same ratios.
IF
If
Compare the ratios of the sides to find out whether the two rectangles are similar:
Therefore, the rectangles are not similar.
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True or false: Rhombus Rhombus .
Statement 1: and
Statement 2: The area of Rhombus is 49 times that of Rhombus .
True or false: Rhombus
Statement 1:
Statement 2: The area of Rhombus
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that corresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary—that is, their angle measures total . Therefore, it is necessary and sufficient to prove just one pair of corresponding angles congruent.
The two statements together give no information about the measures of any of the angles of the rhombus. Therefore, together, they do not answer the question of whether they are similar or not.
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that corresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary—that is, their angle measures total
The two statements together give no information about the measures of any of the angles of the rhombus. Therefore, together, they do not answer the question of whether they are similar or not.
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True or false: Rhombus Rhombus .
Statement 1: and are both angles.
Statement 2: The area of Rhombus is four times that of Rhombus .
True or false: Rhombus
Statement 1:
Statement 2: The area of Rhombus
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that coresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary - that is, their angle measures total . Therefore, it is neccessary and sufficient to prove just one pair of corresponding angles congruent.
Assume Statement 1 alone. is a angle, so any angle consecutive to it, which includes , is supplementary to it—that is, the angle measures total . This makes a angle. Its corresponding angle in Rhombus is , which is a angle. Since and are noncongruent, it follows that Rhombus Rhombus . (Note that it can be demonstrated that the rhombuses are similar, but the correct statement is Rhombus Rhombus .)
Statement 2 alone provides no useful information; the relationship between the areas of the rhombuses is irrelevant.
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that coresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary - that is, their angle measures total
Assume Statement 1 alone.
Statement 2 alone provides no useful information; the relationship between the areas of the rhombuses is irrelevant.
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True or false: Rhombus Rhombus .
Statement 1:
Statement 2:
True or false: Rhombus
Statement 1:
Statement 2:
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that coresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary—that is, their angle measures total . Therefore, it is neccessary and sufficient to prove just one pair of corresponding angles congruent.
Assume Statement 1 alone. and are not corresponding angles, so their congruence does not prove the rhombuses are similar; however it does not prove they are not similar either; for example, two squares are both rhombuses with four right angles, so they are similar and fit this condition.
Assume Statement 2 alone. and are two angles of the same rhombus, so similarity cannot be proved or disproved without information about the other rhombus.
Now assume both statements. and are consecutive angles of Rhombus ; a rhombus being a parallelogram, the degree measures of the angles total . From Statement 2, they are congruent, so each measures . Since from Statement 1, also measures . Since each parallelogram has at least one right angle, each has four right angles. Therefore, corresponding angles are congruent, so the rhombuses are similar.
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
All four sides of a rhombus are congruent, so it easily follows that corresponding sides of two rhombuses are in proportion, regardless of whether they are similar or not; it is therefore necessary and sufficient to prove that coresponding angles are congruent. Also, since a rhombus is a parallelogram, opposite angles are congruent and consecutive angles are supplementary—that is, their angle measures total
Assume Statement 1 alone.
Assume Statement 2 alone.
Now assume both statements.
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Isosceles Trapezoid has bases and .
Isosceles Trapezoid has bases and .
True or false:
Trapezoid Trapezoid
Statement 1: and are both angles.
Statement 2: and
Isosceles Trapezoid
Isosceles Trapezoid
True or false:
Trapezoid
Statement 1:
Statement 2:
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent and that their corresponding sides are in proportion.
We show that Statement 1 alone provides insufficient information by examining two cases.
Case 1: Trapezoid Trapezoid , with a angle.
A pair of base angles of an isosceles trapezoid are congruent, so, since measures , so does . The leg angles of a trapezoid have measures whose sum is , so and measure . By congruence of corresponding angles, , so measures , and the conditions of Statement 1 are met. Furthermore, two congruent triangles are also similar, so Trapezoid Trapezoid .
Case 2: Examine the figure below, in which . Note that these congruent upper bases have been superimposed upon each other:
The trapezoids are isosceles since their base angles are congruent; also, the conditions of Statement 1 are met. However, , but . The sides are not in proportion, so the trapezoids are not similar.
Assume Statement 2 alone. Two congruent trapezoids whose side lengths fit the conditions of the statement are also similar. But examine this diagram, in which , , and . Note that the congruent upper bases have been superimposed upon each other:
The conditions of Statement 2 are met, but , so the trapezoids are not similar.
Now assume both statements to be true. As stated before, it follows from Statement 1 that all corresponding angles are congruent. and , so it follows from the Division Property of Equality that
It remains to be demonstrated that is equal to the above ratios as well. If the diagonals and are constructed, and are formed; since and , by the Side-Angle-Side Similarity Theorem, . It follows that , and by angle addition, since , it follows that . From the Angle-Angle Postulate, the other two triangles formed are similar—that is, —and it follows that . Therefore, all four sides of the trapezoids are in proportion, and the trapezoids are similar.
To prove two figures similar, we must prove that their corresponding angles are congruent and that their corresponding sides are in proportion.
We show that Statement 1 alone provides insufficient information by examining two cases.
Case 1: Trapezoid
A pair of base angles of an isosceles trapezoid are congruent, so, since
Case 2: Examine the figure below, in which
The trapezoids are isosceles since their base angles are congruent; also, the conditions of Statement 1 are met. However,
Assume Statement 2 alone. Two congruent trapezoids whose side lengths fit the conditions of the statement are also similar. But examine this diagram, in which
The conditions of Statement 2 are met, but
Now assume both statements to be true. As stated before, it follows from Statement 1 that all corresponding angles are congruent.
It remains to be demonstrated that
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Isosceles Trapezoid has bases and .
Isosceles Trapezoid has bases and .
True or false:
Trapezoid Trapezoid
Statement 1:
Statement 2:
Isosceles Trapezoid
Isosceles Trapezoid
True or false:
Trapezoid
Statement 1:
Statement 2:
Tap to reveal answer
To prove two figures similar, we must prove that their corresponding angles are congruent and that their corresponding sides are in proportion.
Assume both statements are true. We show that they provide insufficient information by examining two scenarios.
Case 1: Trapezoid Trapezoid , then and , so the conditions of both statements are met; also, since the trapezoids are congruent, they are also similar.
Now examine isosceles trapezoid below, in which , , , and are positioned on the bases so that and .
Since and , Quadrilateral is a parallelogram, and ; similarly, . Therefore, Trapezoid is also isosceles. Also, by the Corresponding Angles Theorem, and , and the conditions of both statements are met. However, corresponding sides are not in proportion, since , but ; consequently, the trapezoids are not similar.
To prove two figures similar, we must prove that their corresponding angles are congruent and that their corresponding sides are in proportion.
Assume both statements are true. We show that they provide insufficient information by examining two scenarios.
Case 1: Trapezoid
Now examine isosceles trapezoid
Since
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Isosceles Trapezoid has bases and .
Isosceles Trapezoid has bases and .
True or false:
Trapezoid Trapezoid
Statement 1:
Statement 2:
Isosceles Trapezoid
Isosceles Trapezoid
True or false:
Trapezoid
Statement 1:
Statement 2:
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To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
Assume both statements are true. We show that they provide insufficient information by examining two scenarios.
If Trapezoid Trapezoid , then and , so the conditions of both statements are met; also, since the trapezoids are congruent, they are also similar.
Now examine isosceles trapezoid below, in which , , , and are positioned on the bases so that and .
Since and , Quadrilateral is a parallelogram, and ; similarly, . Therefore, Trapezoid is also isosceles, and the conditions of both statements are met. However, corresponding sides are not in proportion, since , but ; consequently, the trapezoids are not similar.
To prove two figures similar, we must prove that their corresponding angles are congruent, and that their corresponding sides are in proportion.
Assume both statements are true. We show that they provide insufficient information by examining two scenarios.
If Trapezoid
Now examine isosceles trapezoid
Since
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What is the perimeter of Rhombus ?
Statement 1:
Statement 2:
What is the perimeter of Rhombus
Statement 1:
Statement 2:
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Each statement gives the length of one diagonal of the rhombus. Knowing one diagonal is not enough to give the perimeter of the rhombus.
Knowing the lengths of both diagonals, which is the case if both statements are assumed, is enough to determine the perimeter. The rhombus in question, along with its diagonals, is as shown below:
As marked in the diagram, the diagonals are perpendicular, and they are also are each other's bisector. It follows from the given lengths that and , so can be calculated using the Pythagorean Theorem. The perimeter is four times , since all sides of a rhombus are congruent.
Each statement gives the length of one diagonal of the rhombus. Knowing one diagonal is not enough to give the perimeter of the rhombus.
Knowing the lengths of both diagonals, which is the case if both statements are assumed, is enough to determine the perimeter. The rhombus in question, along with its diagonals, is as shown below:
As marked in the diagram, the diagonals are perpendicular, and they are also are each other's bisector. It follows from the given lengths that
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True or false: Rhombus Rhombus .
Statement 1:
Statement 2:
True or false: Rhombus
Statement 1:
Statement 2:
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Assume Statement 1 alone. A rhombus being a parallelogram, its opposite angles and its adjacent angles are supplementary. From this fact and Statement 1 alone, it follows that
, , , and .
By definition of a rhombus, all of its sides are congruent. By substitution,
.
All side proportions hold as well as all angle congruences, so the similarity statement holds.
Assume Statement 2 alone. Construct the diagonals of the rhombuses, as follows:
In each rhombus, the diagonals are each other's perpendicular bisector. If
then
Since , both angles being right, it follows via the Side-Angle-Side Smiilarity Theorem that
,
and , by similarity,
.
By a similar argument,
,
and by angle addition,
.
As with Statement 1 alone, congruence of one set of corresponding angles in two rhombuses leads to the similarity of the two.
Assume Statement 1 alone. A rhombus being a parallelogram, its opposite angles and its adjacent angles are supplementary. From this fact and Statement 1 alone, it follows that
By definition of a rhombus, all of its sides are congruent. By substitution,
All side proportions hold as well as all angle congruences, so the similarity statement holds.
Assume Statement 2 alone. Construct the diagonals of the rhombuses, as follows:
In each rhombus, the diagonals are each other's perpendicular bisector. If
then
Since
and , by similarity,
By a similar argument,
and by angle addition,
As with Statement 1 alone, congruence of one set of corresponding angles in two rhombuses leads to the similarity of the two.
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