### All GMAT Math Resources

## Example Questions

### Example Question #1 : Dsq: Calculating An Angle Of A Line

What is the measure of ?

Statement 1: is complementary to an angle that measures .

Statement 2: is adjacent to an angle that measures .

**Possible Answers:**

BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.

Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.

EITHER statement ALONE is sufficient to answer the question.

BOTH statements TOGETHER are insufficient to answer the question.

Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.

**Correct answer:**

Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.

Complementary angles have degree measures that total , so the measure of an angle complementary to a angle would have measure . If Statement 1 is assumed, then .

Statement 2 gives no useful information. Adjacent angles do not have any numerical relationship; they simply share a ray and a vertex.

### Example Question #2 : Dsq: Calculating An Angle Of A Line

Note: Figure NOT drawn to scale.

Refer to the above diagram.

What is the measure of ?

Statement 1:

Statement 2:

**Possible Answers:**

EITHER statement ALONE is sufficient to answer the question.

Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.

BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.

Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.

BOTH statements TOGETHER are insufficient to answer the question.

**Correct answer:**

Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.

If we only know that , then we cannot surmise anything from the diagram about the measure of . But and are vertical angles, which must be congruent, so if we know , then also.

### Example Question #3 : Dsq: Calculating An Angle Of A Line

and are supplementary angles. Which one has the greater measure?

Statement 1:

Statement 2: is an obtuse angle.

**Possible Answers:**

EITHER statement ALONE is sufficient to answer the question.

BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.

BOTH statements TOGETHER are insufficient to answer the question.

**Correct answer:**

By definition, if and are supplementary angles, then .

If Statement 1 is assumed and , then . This does not answer our question, since, for example, it is possible that and , or vice versa.

If Statement 2 is assumed, then , and subsequently, ; by transitivity, .

### Example Question #2 : Dsq: Calculating An Angle Of A Line

Note: Figure NOT drawn to scale.

Refer to the above diagram. What is the measure of ?

Statement 1:

Statement 2: is a angle.

**Possible Answers:**

BOTH statements TOGETHER are insufficient to answer the question.

EITHER statement ALONE is sufficient to answer the question.

**Correct answer:**

EITHER statement ALONE is sufficient to answer the question.

Assume Statement 1 alone. Since and form a linear pair, their measures total . Therefore, this fact, along with Statement 1, form a system of linear equations, which can be solved as follows:

The second equation can be rewritten as

and a substitution can be made:

Assume Statement 2 alone. and are a pair of vertical angles, which have the same measure, so .

### Example Question #3 : Dsq: Calculating An Angle Of A Line

Note: You may assume that and are not parallel lines, but you may *not* assume that and are parallel lines unless it is specifically stated.

Refer to the above diagram. Is the sum of the measures of and less than, equal to, or greater than ?

Statement 1:

Statement 2:

**Possible Answers:**

BOTH statements TOGETHER are insufficient to answer the question.

EITHER statement ALONE is sufficient to answer the question.

**Correct answer:**

EITHER statement ALONE is sufficient to answer the question.

Assume Statement 1 alone. and form a linear pair of angles, so their measures total ; the same holds for and . Therefore,

Assume Statement 2 alone. and form a linear pair of angles, so their measures total ; the same holds for and . Therefore,

, , , and are the four angles of Quadrilateral , so their degree measures total 360. Therefore,

### Example Question #4 : Dsq: Calculating An Angle Of A Line

Find the angle made by and the -axis.

I) goes through the origin and the point .

II) makes a degree angle between itself and the -axis.

**Possible Answers:**

Neither statement is sufficient to answer the question. More information is needed.

Statement I is sufficient to answer the question, but statement II is not sufficient to answer the question.

Either statement is sufficient to answer the question.

Both statements are needed to answer the question.

Statement II is sufficient to answer the question, but statement I is not sufficient to answer the question.

**Correct answer:**

Either statement is sufficient to answer the question.

To find the angle of the line, recall that each quadrant has 90 degrees

I) Tells us that the line has a slope of one. This means that if we make a triangle using our line, the x-axis and a line coming up from the x-axis at 90 degrees we will have a 45/45/90 triangle. Therefore, I) tells us that our angle is 45 degrees.

II) Tells us that the line makes a 45 degree angle between itself and the y-axis. Therefore:

Therfore, we could use either statement.

### Example Question #5 : Dsq: Calculating An Angle Of A Line

Note: Figure NOT drawn to scale.

Refer to the above diagram. What is the measure of ?

Statement 1:

Statement 2:

**Possible Answers:**

EITHER statement ALONE is sufficient to answer the question.

BOTH statements TOGETHER are insufficient to answer the question.

**Correct answer:**

Assume Statement 1 alone. and are a pair of vertical angles and are therefore congruent, so the statement

can be rewritten as

, , and together form a straight angle, so their measures total ; therefore,

But without further information, the measure of cannot be calculated.

Assume Statement 2 alone. and are a pair of vertical angles and are therefore congruent, so the statement

can be rewritten as

### Example Question #6 : Dsq: Calculating An Angle Of A Line

Note: Figure NOT drawn to scale.

Refer to the above figure. Evaluate .

Statement 1: and are complementary.

Statement 2:

**Possible Answers:**

EITHER statement ALONE is sufficient to answer the question.

BOTH statements TOGETHER are insufficient to answer the question.

**Correct answer:**

Assume Statement 1 alone. and are vertical from and , respectively, so and . and form a complementary pair, so, by definition

and by substitution,

.

Assume Statement 2 alone. Since is a right triangle whose hypotenuse is times as long as a leg, it follows that is a 45-45-90 triangle, so .

, , , and together form a straight angle, so their degree measures total .

But without further information, the sum of the degree measures of only and cannot be calculated.

### Example Question #7 : Dsq: Calculating An Angle Of A Line

Note: Figure NOT drawn to scale.

Refer to the above diagram. What is the measure of ?

Statement 1: is a angle.

Statement 2:

**Possible Answers:**

BOTH statements TOGETHER are insufficient to answer the question.

EITHER statement ALONE is sufficient to answer the question.

**Correct answer:**

Statement 1 alone gives insufficient information to find the measure of .

, , and together form a angle; therefore,

, so by substitution,

But with no further information, the measure of cannot be calculated.

Statement 2 alone gives insufficient information for a similar reason. , , and together form a angle; therefore,

Since , we can rewrite this statement as

Again, with no further information, the measure of cannot be calculated.

Assume both statements to be true. and are a pair of vertical angles, so , and . Since , then . Also,

By substitution,

### Example Question #8 : Dsq: Calculating An Angle Of A Line

Note: You may assume that and are not parallel lines, but you may *not* assume that and are parallel lines unless it is specifically stated.

Refer to the above diagram. Is the sum of the measures of and less than, equal to, or greater than ?

Statement 1: There exists a point such that lies on and lies on .

Statement 2: Quadrilateral is not a trapezoid.

**Possible Answers:**

BOTH statements TOGETHER are insufficient to answer the question.

EITHER statement ALONE is sufficient to answer the question.

**Correct answer:**

Assume Statement 1 alone. Since exists and includes , and are one and the same—and this is . Similarly, is . This means that and have a point of intersection, which is . Since falls between and and falls between and , the lines intersect on the side of that includes points and . By Euclid's Fifth Postulate, the sum of the measures of and is less than .

Assume Statement 2 alone. Since it is given that , the other two sides, and are parallel if and only if Quadrilateral is a trapezoid, which it is not. Therefore, and are not parallel, and the sum of the degree measures of same-side interior angles and is not equal to . However, without further information, it is impossible to determine whether the sum of the measures is less than or greater than .