Right Angles

Right angles are angles that have a measure of exactly 90 degrees.

N

F

A                        D

B                         K

Theorem: If two angles are right angles, then they are congruent. Here is how we can prove this theorem. Given:  angle A is a right angle.             angle B is a right angle. Prove:  angle A is congruent to             angle B. Statements                                   Reasons 1......................                         1. given 2. Measure of angle A             2.  Right angles have a is  90 degrees.                           measure of 90 degrees. 3. Measure of angle B              3. Same as step 2. is 90 degrees. 4. angle A is congruent to        4. if 2 angles have the angle B.                                    same measure then they                                                   are congruent. Note: You cannot assume right angles.