The following is an incomplete paragraph proving that the opposite sides of parallelogram abcd are congruent. according to the giving information, ab dc and bc ad. construct diagonal a c with a straight edge. it is congruent to itself by the reflexive property of equality. angles bac and dca are congruent by the alternate interior angles theorem. angle bca & dac are congruent but the same by cpctc, opposite sides ab and cd, as well as side bc and da , are congruent. which sentence accurately complete the proof