1. Unit 1: Transformations Day 3: Rotations Standard

2. Warm Up # 3 8.27.2014 Have out Homework
Write Rules for the following (#1-3)
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 (using words):
(x,y)  (-x, y)

3. Essential Question #4
How can coordinates be used to describe rotations?

4. 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***

5. Counter Clockwise

6. Let’s explore Rotations Together!
You need 4 small pieces of graph paper.
Place a labeled coordinate plane on each sheet

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

8. 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.
Complete the worksheets in pairs/groups. The goal is to develop a better understanding of rotation rules

9. Example 1
Write the rule and graph the image of a 90° rotation

10. Example 2
Given the preimage coordinates, what are the coordinates of the image after a 90⁰ clockwise rotation about the image.
A (4, 7)
B (-3, 2)
C (5, -1)

11. Example 3
A) Identify the transformation that occurred. B) Write the rule for the transformation.

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

13. Definition: 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 (≅)

14. Assessment
3-2-1: Write down 3 things you learned this week, 2 things you have a question about, and 1 thing you found interesting.
Homework: Page 7 in packet
Standard: for questions 4 – 6 you do not have to graph the image, just identify the coordinates!