1. StatementsReasons 1. ________________________________ 2.  1   2 3. ________________________________ 4. ________________________________ 1. ______________________________ 2. _____________________________ 3. If lines are parallel, then corresponding angles are congruent. 4. _____________________________ Proof #1 Proof of Alternate Exterior Angles congruent: Given: l || m Prove:  1   3 Proof #2 Proof of Same-Side Exterior Angles supplementary: Given: l || m Prove:  1 is supplementary to  3 StatementsReasons 1. ________________________________ 3. m  2 = m  3;  2   3 2. ______ + ______ = 180 4. ______ + ______ = 180 5. ________________________________ 1. ______________________________ 2. Angle Addition Postulate 4. _____________________________ 5. Definition of ___________________ 3. _____________________________ _____________________________ Geometry / Trig 2Name __________________________ 3.2 Properties of Parallel Lines & ProofsDate ___________________________ Homework 1 2 3 l m t 1 2 3 l m t

2. StatementsReasons 1. ________________________________ 2.  1   ____ ; ______ = ______ 3. ________________________________ 4. ________________________________ 1. ______________________________ 2. If lines are parallel, then alternate interior angles are congruent. 3. Angle Addition Postulate 4. Substitution Proof #3 Given: k || l Prove:  1 is supplementary to  7 5. ________________________________5. _____________________________ StatementsReasons 1. a || b 2.  6   8 4. ________________________________ 5. ________________________________ 1. ______________________________ 2. _____________________________ _____________________________ 4. If lines are parallel, then alternate interior angles are congruent. 5. _____________________________ Proof #4 Given: a || b ; c || d Prove:  6   11 Geometry / Trig 2 3.2 Properties of Parallel Lines & Proofs Homework 3. ________________________________3. Given 1 2 7 k l t 6 5 48 3 c d ba 4231 8675 1210119 16141513

3. StatementsReasons 1. ________________________________ 2.  4   ___; m  4 = m  ___ 3.  ___   ___; m  ___ = m  ___ 4.  4   5; m  4 = m  5 1. Given 2. Vertical Angle Theorem 4. _____________________________ Proof #5 Given: a || b ; c || d Prove:  4 is supplementary to  9 Geometry / Trig 2 3.2 Properties of Parallel Lines & Proofs Homework 3. _____________________________ _____________________________ 5. ________________________________5. Given 7. ________________________________ 6. If lines are parallel, then ___________ ______________________________ 8. ________________________________8. _____________________________ 9. ________________________________9. Definition of ____________________ c d ba 4231 8675 1210119 16141513 6.  5 and  9 are supplementary 7. Definition of supplementary angles