What is the missing reason in the proof? statements reasons 1. ab ∥ cd; bc ∥ da 1. given 2. quadrilateral abcd is a ▱ 2. definition of parallelogram 3. ab ≅ cd; bc ≅ da 3. opposite sides of a parallelogram are ≅ 4. ac ≅ ac 4. reflexive property 5. δabc ≅ δcda 5. ? perpendicular bisector theorem pythagorean theorem hl theorem sss congruence theorem