1. Lesson 2.4 Congruent Supplements and Complements Objective: To prove angles congruent by means of four new theorems

2. In the diagram below, is supplementary to, and is also supplementary to. How large is ? Now calculate. How does compare with ? Your results will illustrate (but not prove) the following theorem. A 70

3. Theorem 4 If angles are supplementary to the same angle, then they are congruent Given: Prove: 3 4 5

4. Theorem 5 If angles are supplementary to congruent angles, then they are congruent Given: Prove: H F G J

5. Theorem 6 If angles are complementary to the same angle, then they are congruent. Theorem 7 If angles are complementary to congruent angles, then they are congruent.

6. Let’s try so more… Given: Prove: StatementsReasons 1. 2. 1. 3. 4. 3. 4. 123 4

7. Given: Conclusion: StatementsReasons 1. 2. 1. 3. B A C D ?

8. StatementsReasons 1. 2. 1. 3. 4. 3. 4. 5. 6. 5. 6. H E F G J Given: Prove: Diagram as shown

9. StatementsReasons 1. 2. 1. 3. 4. 3. 4. 5. 6. 5. 6. Given: Prove: K RP M O

10. Lesson 2.4 Worksheet Homework Summary… You need to memorize the theorems. How are you going to remember them?