1. Congruent Angles

2. Vertical Angles Theorem Vertical angles are congruent.

3. Statements Reasons 1 and 2 are vertical angles GIVEN
1 and 2 are supplementary
2 and 3 are supplementary
s in a linear pair
Are supplementary
m1 + m2 = 180
m2 + m3 = 180
Definition of
Supplementary
m1 + m2 = m2 + m3
Symmetric & Transitive
m1 = m3
Subtraction Property
1  3
Definition of Congruent

4. SOME OTHER THEOREMS If 2 angles are supplementary to the same angle (or  s), then they are congruent.

5. If 2 angles are complementary to the same angle (or  s), , they are congruent.

6. All right angles are congruent.

7. If two angles are congruent and supplementary, then each is a right angle.

8. Remember Which angles are congruent. . Vertical 
Remember Which angles are congruent?  Vertical  Supplementary to same  Complementary to same  All right angles