(03.04 MC) The following is an incomplete paragraph proving that the opposite sides of parallelogram
ABCD are congruent:
B
С
A
According to the given information, AB || DC and BC || AD. Construct diagonal AC with a
straightedge. It is congruent to itself by the Reflexive Property of Equality. Angles BAC and
DCA are congruent by the Alternate Interior Angles Theorem. Angles BCA and DAC are
congruent by the same theorem. By CPCTC, opposite sides AB and CD, as well as
sides BC and DA, are congruent.
Which sentence accurately completes the proof? (5 points)