# Example proofs

- Author:
- Lind, Jon

## 1. Vertical Angles are congruent

Go through the steps for this proof. Pay attention to the notation used for

**rotations**.## 1. Narrative Proof

First, draw segment AD to make triangle AED.
Then, rotate triangle AED 180° around E. Now angle A'ED' is congruent with angle BEC.
Since angle A'ED' came from a translation of angle AED, angle AED is also congruent with angle BEC.

## 2. The angles of a triangle add up to 180°

Go through the steps for this proof. Pay attention to the notation used for

**translations**.## 2. Narrative proof

Your turn! Write the steps for this proof in narrative form.

## 3. A parallelogram with congruent adjacent sides is a rhombus

Go through the steps for this proof. Pay attention to the notation used for

**reflections**.## 3. Narrative proof

Your turn! Write the steps for this proof in narrative form.