# IM Geometry U1L20 Transformations, Transversals, and Proof

Topic:
Geometry

## 20.1 Figure A

What is the measure of angle x, in degrees? (Just type the number.)

## 20.1 Figure B

What is the measure of angle x, in degrees? (Just type the number.)

## 20.1 Figure C

What is the measure of angle x, in degrees? (Just type the number.)

## 20.1 Figure D

What is the measure of angle x, in degrees? (Just type the number.)

## 20.2

Translate lines AE and CD by the directed line segment from B to C. The image points should be labeled appropriately as A', B', etc. This is easiest if you set yourself up to translate all points at once. STEPS TO DO THIS: 1) Draw a vector from B to C. 2) Click the transformations button and select the "translate by vector" tool. 3) Click and drag to highlight ALL points on both lines. 4) Click the vector from B to C to complete the translation. 5) Use the line tool to draw line A'E'.

1. What is true about lines AE and A'E'?

Select all that apply
• A
• B
• C

Identify congruent angles. For each pair of congruent angles that you find, explain how you know the angles are congruent.

## 20.3

Rotate line AE by 180° around point C. The image points should be labeled appropriately as A', B', etc. It is a little tricky to get the applet to cooperate for this, so we will need to rotate each point one at a time! STEPS TO DO THIS: 1) Click the transformations button and select the "rotate around point" tool. 2) Click point A, then point C. This will rotate point A around center C. Enter the angle (180 degrees). 3) Click point B, then point C. This will rotate point B around center C. Enter the angle (180 degrees). 4) Click point D, then point C. This will rotate point D around center C. Enter the angle (180 degrees). 5) Click point E, then point C. This will rotate point E around center C. Enter the angle (180 degrees). 6) Use the line tool to draw line A'E'.

1. What is true about lines AB and A'B'?

Select all that apply
• A
• B
• C

Identify congruent angles. For each pair of congruent angles that you find, explain how you know the angles are congruent.