Example proofs

1. Vertical Angles are congruent

Go through the steps for this proof. Pay attention to the notation used for [b]rotations[/b].

1. Narrative Proof

First, draw segment AD to make triangle AED.[br]Then, rotate triangle AED 180° around E. Now angle A'ED' is congruent with angle BEC. [br]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 [b]translations[/b].

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 [b]reflections[/b].

3. Narrative proof