Common Core: 8th Grade Math : Grade 8

Study concepts, example questions & explanations for Common Core: 8th Grade Math

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Example Questions

Example Question #6 : Understand Similarity Of Two Dimensional Figures: Ccss.Math.Content.8.G.A.4

Are the two dimensional shapes shown on the coordinate plane provided similar? If yes, do the shapes show a transformation or a dilation? 


6

Possible Answers:

Yes, transformation

No

Yes, both a transformation and dilation 

Yes, dilation

Correct answer:

Yes, both a transformation and dilation 

Explanation:

In order for two shapes to be similar, they must be the same shape. If the shapes are the same, but are a different size or facing a different direction, then the shapes can still be similar if and only if they have gone through a dilation or a transformation. 

Let's recall our key terms:

Dilation: A dilation creates an image of the same shape, but of a different size. Dilations are always done with a certain scale factor, and the scale factor must be equal for all sides of the shape. 

Transformation: A transformation can be described in three ways:

  • Rotation: A rotation means turning an image, shape, line, etc. around a central point.
  • Translation: A translation means moving or sliding an image, shape, line, etc. over a plane.
  • Reflection: A reflection mean flipping an image, shape, line, etc. over a central line. 

The yellow rectangle is smaller than the blue rectangle. In fact, both the length and the width are half the size; thus, the shape has gone through a dilation. The yellow rectangle is also in a different position; thus, the shape has gone through a transformation.  

 

Example Question #7 : Understand Similarity Of Two Dimensional Figures: Ccss.Math.Content.8.G.A.4

Are the two dimensional shapes shown on the coordinate plane provided similar? If yes, do the shapes show a transformation or a dilation? 


7

Possible Answers:

No

Yes, both a transformation and dilation 

Yes, transformation

Yes, dilation 

Correct answer:

Yes, both a transformation and dilation 

Explanation:

In order for two shapes to be similar, they must be the same shape. If the shapes are the same, but are a different size or facing a different direction, then the shapes can still be similar if and only if they have gone through a dilation or a transformation. 

Let's recall our key terms:

Dilation: A dilation creates an image of the same shape, but of a different size. Dilations are always done with a certain scale factor, and the scale factor must be equal for all sides of the shape. 

Transformation: A transformation can be described in three ways:

  • Rotation: A rotation means turning an image, shape, line, etc. around a central point.
  • Translation: A translation means moving or sliding an image, shape, line, etc. over a plane.
  • Reflection: A reflection mean flipping an image, shape, line, etc. over a central line. 

The yellow rectangle is smaller than the blue rectangle. In fact, both the length and the width are half the size; thus, the shape has gone through a dilation. The yellow rectangle is also in a different position; thus, the shape has gone through a transformation.  

 

Example Question #8 : Understand Similarity Of Two Dimensional Figures: Ccss.Math.Content.8.G.A.4

Are the two dimensional shapes shown on the coordinate plane provided similar? If yes, do the shapes show a transformation or a dilation? 

8

Possible Answers:

Yes, both a transformation and dilation 

Yes, dilation 

No

Yes, transformation

Correct answer:

Yes, both a transformation and dilation 

Explanation:

In order for two shapes to be similar, they must be the same shape. If the shapes are the same, but are a different size or facing a different direction, then the shapes can still be similar if and only if they have gone through a dilation or a transformation. 

Let's recall our key terms:

Dilation: A dilation creates an image of the same shape, but of a different size. Dilations are always done with a certain scale factor, and the scale factor must be equal for all sides of the shape. 

Transformation: A transformation can be described in three ways:

  • Rotation: A rotation means turning an image, shape, line, etc. around a central point.
  • Translation: A translation means moving or sliding an image, shape, line, etc. over a plane.
  • Reflection: A reflection mean flipping an image, shape, line, etc. over a central line. 

The yellow rectangle is smaller than the blue rectangle. In fact, both the length and the width are half the size; thus, the shape has gone through a dilation. The yellow rectangle is also in a different position; thus, the shape has gone through a transformation.  

Example Question #381 : Grade 8

Are the two dimensional shapes shown on the coordinate plane provided similar? If yes, do the shapes show a transformation or a dilation? 


9

Possible Answers:

Yes, both a transformation and dilation

Yes, dilation 

Yes, transformation

No

Correct answer:

No

Explanation:

In order for two shapes to be similar, they must be the same shape. If the shapes are the same, but are a different size or facing a different direction, then the shapes can still be similar if and only if they have gone through a dilation or a transformation. 

Let's recall our key terms:

Dilation: A dilation creates an image of the same shape, but of a different size. Dilations are always done with a certain scale factor, and the scale factor must be equal for all sides of the shape. 

Transformation: A transformation can be described in three ways:

  • Rotation: A rotation means turning an image, shape, line, etc. around a central point.
  • Translation: A translation means moving or sliding an image, shape, line, etc. over a plane.
  • Reflection: A reflection mean flipping an image, shape, line, etc. over a central line. 

The yellow rectangle is smaller than the blue rectangle, but a dilation did not occur because because the scale factor for the length and the width are not equal to each other; thus, the shapes are not similar. 

 

Example Question #64 : Geometry

Are the two dimensional shapes shown on the coordinate plane provided similar? If yes, do the shapes show a transformation or a dilation? 

10

Possible Answers:

Yes, dilation 

Yes, both a transformation and dilation 

No

Yes, transformation

Correct answer:

No

Explanation:

In order for two shapes to be similar, they must be the same shape. If the shapes are the same, but are a different size or facing a different direction, then the shapes can still be similar if and only if they have gone through a dilation or a transformation. 

Let's recall our key terms:

Dilation: A dilation creates an image of the same shape, but of a different size. Dilations are always done with a certain scale factor, and the scale factor must be equal for all sides of the shape. 

Transformation: A transformation can be described in three ways:

  • Rotation: A rotation means turning an image, shape, line, etc. around a central point.
  • Translation: A translation means moving or sliding an image, shape, line, etc. over a plane.
  • Reflection: A reflection mean flipping an image, shape, line, etc. over a central line. 

The yellow rectangle is smaller than the blue rectangle, but a dilation did not occur because because the scale factor for the length and the width are not equal to each other; thus, the shapes are not similar. 

 

Example Question #11 : Understand Similarity Of Two Dimensional Figures: Ccss.Math.Content.8.G.A.4

Are the two dimensional shapes shown on the coordinate plane provided similar? If yes, do the shapes show a transformation or a dilation? 


11

Possible Answers:

Yes, transformation

Yes, dilation 

Yes, both a transformation and dilation

No

Correct answer:

No

Explanation:

In order for two shapes to be similar, they must be the same shape. If the shapes are the same, but are a different size or facing a different direction, then the shapes can still be similar if and only if they have gone through a dilation or a transformation. 

Let's recall our key terms:

Dilation: A dilation creates an image of the same shape, but of a different size. Dilations are always done with a certain scale factor, and the scale factor must be equal for all sides of the shape. 

Transformation: A transformation can be described in three ways:

  • Rotation: A rotation means turning an image, shape, line, etc. around a central point.
  • Translation: A translation means moving or sliding an image, shape, line, etc. over a plane.
  • Reflection: A reflection mean flipping an image, shape, line, etc. over a central line. 

The yellow rectangle is smaller than the blue rectangle, but a dilation did not occur because because the scale factor for the length and the width are not equal to each other; thus, the shapes are not similar. 

 

Example Question #12 : Understand Similarity Of Two Dimensional Figures: Ccss.Math.Content.8.G.A.4

Are the two dimensional shapes shown on the coordinate plane provided similar? If yes, do the shapes show a transformation or a dilation? 


12

Possible Answers:

No

Yes, both a transformation and dilation 

Yes, dilation 

Yes, transformation

Correct answer:

No

Explanation:

In order for two shapes to be similar, they must be the same shape. If the shapes are the same, but are a different size or facing a different direction, then the shapes can still be similar if and only if they have gone through a dilation or a transformation. 

Let's recall our key terms:

Dilation: A dilation creates an image of the same shape, but of a different size. Dilations are always done with a certain scale factor, and the scale factor must be equal for all sides of the shape. 

Transformation: A transformation can be described in three ways:

  • Rotation: A rotation means turning an image, shape, line, etc. around a central point.
  • Translation: A translation means moving or sliding an image, shape, line, etc. over a plane.
  • Reflection: A reflection mean flipping an image, shape, line, etc. over a central line. 

The yellow rectangle is smaller than the blue rectangle, but a dilation did not occur because because the scale factor for the length and the width are not equal to each other; thus, the shapes are not similar. 

 

Example Question #1 : Use Informal Arguments To Establish Facts About The Angle Sum And Exterior Angle Of Triangles: Ccss.Math.Content.8.G.A.5

The image provided contains a set of parallel lines,  and , and a transversal line, . If angle  is equal to , then which of the other angles is equal to 

2

Possible Answers:

Correct answer:

Explanation:

First, we need to define some key terms:

Parallel Lines: Parallel lines are lines that will never intersect with each other. 

Transversal Line: A transversal line is a line that crosses two parallel lines.

In the the image provided, lines  and  are parallel lines and line  is a transversal line because it crosses the two parallel lines.

It is important to know that transversal lines create angle relationships:

  • Vertical angles are congruent
  • Corresponding angles are congruent
  • Alternate interior angles are congruent
  • Alternate exterior angles are congruent

Let's look at angle  in the image provided below to demonstrate our relationships. 

1

Angle  and  are vertical angles.

Angle  and  are corresponding angles. 

Angle  and  are exterior angles. 

Angle  is an exterior angle; therefore, it does not have an alternate interior angle. In this image, the alternate interior angles are the angle pairs  and  as well as angle  and 

For this problem, we want to find the angle that is congruent to angle . Based on our answer choices, angle  and  are vertical angles; thus, both angle  and  are congruent and equal 

Example Question #382 : Grade 8

The image provided contains a set of parallel lines,  and , and a transversal line, . If angle  is equal to , then which of the other angles is equal to 

2

 

Possible Answers:

Correct answer:

Explanation:

First, we need to define some key terms:

Parallel Lines: Parallel lines are lines that will never intersect with each other. 

Transversal Line: A transversal line is a line that crosses two parallel lines.

In the the image provided, lines  and  are parallel lines and line  is a transversal line because it crosses the two parallel lines.

It is important to know that transversal lines create angle relationships:

  • Vertical angles are congruent
  • Corresponding angles are congruent
  • Alternate interior angles are congruent
  • Alternate exterior angles are congruent

Let's look at angle  in the image provided below to demonstrate our relationships. 

1

Angle  and  are vertical angles.

Angle  and  are corresponding angles. 

Angle  and  are exterior angles. 

Angle  is an exterior angle; therefore, it does not have an alternate interior angle. In this image, the alternate interior angles are the angle pairs  and  as well as angle  and 

For this problem, we want to find the angle that is congruent to angle . Based on our answer choices, angle  and  are corresponding angles; thus, both angle  and  are congruent and equal 

Example Question #2 : Use Informal Arguments To Establish Facts About The Angle Sum And Exterior Angle Of Triangles: Ccss.Math.Content.8.G.A.5

The image provided contains a set of parallel lines,  and , and a transversal line, . If angle  is equal to , then which of the other angles is equal to 

2

 

 

Possible Answers:

Correct answer:

Explanation:

First, we need to define some key terms:

Parallel Lines: Parallel lines are lines that will never intersect with each other. 

Transversal Line: A transversal line is a line that crosses two parallel lines.

In the the image provided, lines  and  are parallel lines and line  is a transversal line because it crosses the two parallel lines.

It is important to know that transversal lines create angle relationships:

  • Vertical angles are congruent
  • Corresponding angles are congruent
  • Alternate interior angles are congruent
  • Alternate exterior angles are congruent

Let's look at angle  in the image provided below to demonstrate our relationships. 

1

Angle  and  are vertical angles.

Angle  and  are corresponding angles. 

Angle  and  are exterior angles. 

Angle  is an exterior angle; therefore, it does not have an alternate interior angle. In this image, the alternate interior angles are the angle pairs  and  as well as angle  and 

For this problem, we want to find the angle that is congruent to angle . Based on our answer choices, angle  and  are corresponding angles; thus, both angle  and  are congruent and equal 

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