1. GBK Geometry Jordan Johnson

2. Today’s plan • Greeting • Review Asg #33: Chapter 4 Algebra Review (pp. 181-182): • Exercises 1-25. • Bonus: Respond in complete sentences to the questions below the table of numbers at the top left of p. 182. • Lesson: Transformations & Isometries • Classwork / Lab • Homework / Questions • Clean-up

3. Transformations • A transformation is a 1:1 correspondence between points. • Practical examples: • Points on land  points on a map • Dragging / scaling an image in Photoshop • Zooming in/out while looking at a picture • The figure produced by a transformation is called its image.

4. Transformations

5. Lab exercises • Need: • 1 worksheet • 2-3 sheets of patty paper • Teams of 2-3: • A reader, who reads the instructions, checks that they’re being followed, and writes the answers. • One or two manipulators, who do the folding/drawing according to the instructions.

6. Further instructions • In each transformation: • Choose two points (call them A & B) in the original figure. • Label their corresponding points A’ and B’ in the image. • Measure AA’ and BB’. • Measure AB and A’B’.

7. Questions • What can we say about… • …the distance between points in the original shape and points in the image? • …distances in the original shape and the corresponding distances in the image? • …angles in the original shape and the corresponding angles in the image?

8. Isometries • An isometry is a transformation that preserves distance and angle measure. • Also known as a rigid motion.

9. Homework • Do the following from Chapter 8, Lesson 1, on graph paper: • Set I Exercises 1-7, 22-24. • Set II Exercises 47-58. • Bonus: Set III. • Due Thursday, 12/6 (periods 1 & 2)or Friday, 12/7 (period 7).

10. Clean-up / Reminders • Pick up all trash / items. • Push in chairs (at front and back tables). • See you tomorrow!