1. Transformations – Day 3
Rotations

2. End Warm Up Write Rules for the following Reflection across the x-axis
Reflection across the line y = x
Describe the transformation: (x,y)  (-x, y)
10 minutes
End

3. Warm Up: General Rules for Line Reflections
In your notes, write down the rules for reflection
Reflection across
The x-axis:
The y-axis:
The line y = x:
The line y = -x
10 minutes
End

4. Homework Check

5. Rotation
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***

6. Counter Clockwise

7. Rotations Investigation
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.

8. Group Work Time Keeper: 15 minutes
Resource Manager: Rotations Worksheet
Reader: Read problems out loud to group
Spy Monitor: Check in with other groups if you are stuck

9. Problem 2 Time Keeper: Set 10 minutes
Reader: Read problems out loud to group
Spy Keeper: Check with other groups if you are stuck

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

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

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

13. Discussion
What do OUR three types of transformations have in common?

14. 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 (≅)

15. 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