Example proofs

Author:
00JonLind

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.