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Unit 1- Lesson 5 - Grade 8: Illustrative Mathematics

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18 Questions
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Grade 8 Unit 1
Lesson 5: Coordinate Moves
CC BY 2021 Illustrative Mathematics®
Grade 8 Unit 1
Lesson 5: Coordinate Moves
CC BY 2021 Illustrative Mathematics®
Lesson: Coordinate Moves

Translating Coordinates (Warm Up)

1.

Select all of the translations that take Triangle T to Triangle U. There may be more than one correct answer.

2.

Translate (-3, 0) to (1, 2) .

3.

Translate (2, 1) to (-2, -1) .

4.

Translate (-4, -3) to (0, -1) .

5.

Translate (1, 2) to (2, 1) .

Reflecting Points on the Coordinate Plane

Here is a list of points
A = (0,5,4) B = (4, 5) C = (7, -2) D = (6, 0) E = (0, -3)
6.

On the coordinate plane:
  1. Plot each point and label each with its coordinates.
  2. Using the X-axis as the line of reflection, plot the image of each point.
  3. Label the image of each point with its coordinates.
  4. Include a label using a letter. For example, the image of point A should be labeled A'.

7.

If the point (13, 10) were reflected using the X-axis as the line of reflection, what would be the coordinates of the image? What about (13, -20)? (13, 570)? Explain how you know.


The point R has coordinates (3, 2).
8.

Without graphing, predict the coordinates of the image of point R if point R were reflected using the y-axis as the line of reflection.

9.

Check your answer by finding the image of on the graph.

10.

Label the image of point R as R'.

11.

What are the coordinates of R'?

12.

Suppose you reflect a point using the
y-axis as line of reflection. How would you describe its image?

Transformations of a Segment

Apply each of the following transformations to segment AB.
13.

Rotate segment AB 90 degrees counterclockwise around center B. Label the image of A as C. What are the coordinates of C?

14.

Rotate segment AB 90 degrees counterclockwise around center A. Label the image of B as D. What are the coordinates of D?

15.

Rotate segment AB 90 degrees clockwise around (0, 0). Label the image of A as E and the image of B as F. What are the coordinates of E and F?

16.

Compare the two 90-degree counterclockwise rotations of segment AB. What is the same about the images of these rotations? What is different?


Cool Down: Rotation or Reflection

Rotation or Reflection

One of the triangles pictured is a rotation of triangle ABC and one of them is a reflection.
17.

Identify the center of rotation. And label the rotated image PQR.

18.

Identify the line of reflection. And label the reflected image XYZ.