1. Unit 1 – Day 3
Rotations

2. Warm Up # 1 – Have HW out!!! Write Rules for the following
1) Reflection across the x-axis
2) Reflection across the line y = x
3) A Translation three units up and five units left
4) Describe the transformation: (x,y)  (-x, y)

3. Reflection HW Check

4. 7) Reflection across y = 2
8) Reflection across y = -x
(x, y )  (-x, -y)
9) Reflection across x-axis
(x, y)  (2, -1)
10) Reflection across x = -3
11) Reflection across y-axis
(x, y)  (-x, y)
12) Reflection across y = x
(x, y)  (y, x)

5. How can we use coordinates to rotate a figure?

6. Reflection
Definition: A Rotation is a transformation that turns or spins a figure about a fixed point, often the origin.
*** All rotations are counterclockwise about the origin unless otherwise stated***

7. Counter Clockwise

8. Let’s explore Rotations Together!

9. Group Work
Rotations about the origin have similar algebraic rules as reflections. A rotation, or turning motion, is determined by a point called the center of the rotation and a directed angle of rotation.
Time Keeper: 10 minutes
Resource Manager: Problem 6 Worksheet (1/member)
Reader: Read problems out loud to group
Spy Monitor: Check in with other groups if you are stuck
Page 200 and 201 in book, Skip e and f

10. Question 7 Time Keeper: Set 15 minutes
Resource Manager: Grab worksheet for each member
Reader: Read problems out loud to group
Spy Keeper: Check with other groups if you are stuck
Page 201
Skip c and f

11. General Rules for Rotations
Rotation of
90°
180°
270°
360°

12. Example
Write the rule and graph the image of a 90° rotation

13. Another way to rotate!
Let’s look at another way to rotate without using the rules!

14. Discussion
What do are three types of transformations have in common?

15. Isometry
An isometry is a transformation in which the preimage and image are congruent
What does it mean to be congruent?
Two figures are congruent if they have the exact same size and shape (≅)

16. Assessment
3-2-1: Write down 3 things you learned today, 2 things you have a question about, and 1 thing you found interesting
Homework: Worksheet