### All Common Core: High School - Geometry Resources

## Example Questions

### Example Question #1 : Rotation, Reflection, And Transformation Definitions: Ccss.Math.Content.Hsg Co.A.4

Two pencils are placed equidistance away from one another on a table. If these two pencils are parallel, what is the result after they are reflected.

**Possible Answers:**

The two pencils are now perpendicular.

The two pencils are located on the same line.

None of the answers.

The two pencils do not move.

The two pencils are still parallel.

**Correct answer:**

The two pencils are still parallel.

Before solving this problem recall the definition of a reflection.

Reflection: The transformation of each and every point on a line or figure across some line where is some constant or linear function.

Applying this definition to the situation at hand result in the following depiction. The pencils are represented by the blue and black lines and the reflection line is the red dashed line. After the reflection occurs, the pencils essentially swap positions. Since the pencils were parallel to start with, they remain parallel after the reflection occurred.

Therefore, the correct answer is,

"The two pencils are still parallel."

### Example Question #38 : High School: Geometry

Given a circle that is divided into equal pieces, what is the number of rotations that can occur to keep symmetry?

**Possible Answers:**

None of the answers.

Five

Six

Three

Twelve

**Correct answer:**

Six

Drawing the described circle is the first step in answering this given question.

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until it results in the exact image as originally started with. Since the circle is divided into six equal pieces that means that rotating one of the pieces can be done six different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is six.

### Example Question #39 : High School: Geometry

Given a regular polygon that has sides, calculate the order of rotational symmetry.

**Possible Answers:**

**Correct answer:**

For this particular question recall what rotational symmetry means. For an object to achieve rotational symmetry it must return to its original form. This can be accomplished by rotating the figure or equal parts of the figure in either the clockwise or non clockwise direction.

For this particular problem, it is stated that the polygon is "regular" meaning all sides and angles are equal to one another. It is also said that the polygon has sides. This means that the figure can be rotated times to return to its original form.

Therefore, to obtain rotational symmetry of a regular polygon, it must have an order equal to the number of sides.

Thus, the answer is .

### Example Question #40 : High School: Geometry

Looking at the above image, calculate the order of rotational symmetry of the polygon that is inscribed in the circle.

**Possible Answers:**

**Correct answer:**

For this particular question recall what rotational symmetry means. For an object to achieve rotational symmetry it must return to its original form. This can be accomplished by rotating the figure or equal parts of the figure in either the clockwise or non clockwise direction.

For this particular problem, look at the following image.

The polygon has six sides. This means that the figure can be rotated times to return to its original form.

Therefore, to obtain rotational symmetry of a regular polygon, it must have an order equal to the number of sides.

Thus, the answer is .

### Example Question #41 : Congruence

For an equilateral triangle that is inscribed in a circle, what is the minimum angle rotation that can be done to result in the same triangle orientation?

**Possible Answers:**

None of the answers.

**Correct answer:**

Recall that the circle is degrees. It is also important to recall that an equilateral triangle is a triangle whose side lengths are equal and the angles are equal. When the triangle is inscribed in the circle three lines can be drawn from the vertex on each point to the midpoint of the opposite side. This results in the following image.

From here, calculate the central angle between two points of the triangle. Since the circle is degrees and the triangle is divided into six equal sectors then each sector is degrees. Now, there are two sectors between two points of the triangle. Therefore, the minimum angle rotation that can be done to result in the same triangle is degrees.

### Example Question #42 : Congruence

Given a circle that is divided into equal pieces, what is the number of rotations that can occur to keep symmetry?

**Possible Answers:**

**Correct answer:**

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into equal pieces that means that rotating one of the pieces can be done two different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

### Example Question #41 : Congruence

Given a circle that is divided into equal pieces, what is the number of rotations that can occur to keep symmetry?

**Possible Answers:**

**Correct answer:**

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into equal pieces that means that rotating one of the pieces can be done 8 different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

### Example Question #44 : Congruence

**Possible Answers:**

**Correct answer:**

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into 16 equal pieces that means that rotating one of the pieces can be done different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

### Example Question #41 : Congruence

**Possible Answers:**

**Correct answer:**

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into equal pieces that means that rotating one of the pieces can be done different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

### Example Question #46 : Congruence

**Possible Answers:**

**Correct answer:**

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into equal pieces that means that rotating one of the pieces can be done different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .