According to the given information line ab is parallel to line dc and line bc is parallel to line ad. construct diagonal a c with a straightedge. it is congruent to itself by the reflexive property of equality. angles bca and dac are congruent by the same reasoning. triangles bca and dac are congruent according to the angle-side-angle theorm. by cpctc opposite sides ab and cd, as well as sides bc and da are congruent. which sentence accurately completes the proof? (pictures below