1. Warm-Up
Review of Translations and Reflections:
Solve:
Get a sheet from the table/stool
1. -8x + 2 = 10
and complete.
2. -7y – 23 = 5
3.
y
3
6

2. Essential Question
How do I rotate an object on a coordinate
plane?

3. Rotations
Unit 1, Day 7

4. Common Core GPS
MCC8.G.1: Verify experimentally the properties of rotations,
reflections, and translations:
a. Lines are taken to lines, and line segments to line
segments of the same length.
b. Angles are taken to angles of the same measure.
c. Parallel lines are taken to parallel lines.
MCC8. G. 2: Understand that a two-dimensional figure is
congruent to another if the second can be obtained from
the first by a sequence of rotations, reflections, and
translations; given two congruent figures, describe a
sequence that exhibits the congruence between them.

5. Language of the Standards

6. Rotating:
A rotation can be clockwise or counterclockwise.

7. Angle of Rotation
What does a 90° angle look like?
What does a 180° angle look like?

8. Rotations
Rotations usually occur around the vertex or
origin.
Blue is the original. Red is the new rotated figure. Give the direction and
degrees of each rotation.

9. Rotations around the origin
A general rule for rotating 90°
CounterCLOCKWISE about the origin:
(x, y) becomes (-y, x)
Rotating 180°: (x, y) becomes (-x, -y)
Click for Demonstration

10. Rotations around the origin
A general rule for rotating 90° CLOCKWISE
about the origin:
(x, y) becomes (y, -x)
Did this
Rotating 180°: (x, y) becomes (-x, -y)
Click for Demonstration
change?
Why or why
not…

11. Rotate 90° clockwise about the origin

12. Rotate 90° counterclockwise about
the origin

13. Rotate 180° clockwise about the origin

14. Work Session:
Graph the image using the given transformation.
1. rotate 180° about the origin

16. Write a rule to describe each transformation.

17. 5. Plot the following points: A (5,4), B (2, 6), and C (1, 3).
a. Rotate the triangle 90° clockwise around the origin.
b. What are the coordinates for your new triangle?
A’ __________ B’ __________ C’ __________
c. Would these coordinates be the same if the image
was also reflected across the x-axis? Justify your reasoning.

18. Closing:
What is a rotation on the coordinate plane?
How is it different from a translation or
reflection?