What is the missing reason in the proof? Statements Reasons 1. line segment AB is parallel to line segment CD ; line segment BC is parallel to line segment DA 1. given 2. Quadrilateral ABCD is a parallelogram 2. definition of parallelogram 3. line segment AB is congruent to line segment CD ; line segment BC is congruent to line segment DA 3. opposite sides of a parrallegram are is congruent to 4. line segment AC is congruent to line segment AC 4. refexive property 5. triangle ABC is congruent to triangle CDA 5. ?