1. 2.6 – Proving Statements about Angles Definition: Theorem A true statement that follows as a result of other true statements

2. Right Angle Theorem (2.3) All Right Angles are Congruent

3. Congruent Supplements Theorem (2.4) If two angles are supplementary to the same angle (or to congruent angles) then they are congruent If m<1 + m<2 = 180 o and m<2 + m<3 = 180 o, then <1 <3 1 2 3

4. Congruent Complements Theorem (2.5) If two angles are complementary to the same angle (or to congruent angles) then the two angles are congruent If m<4 + m<5 = 90 o, and m<5 + m<6 = 90 o, then <4 <6 4 5 6

5. Linear Pair Postulate (12) If two angles form a linear pair, then they are supplementary M<1 + m<2 = 180 o 12

6. Vertical Angles Theorem (2.6) Vertical Angles are congruent <1 <3; <2 <4 1 2 3 4