The question is asking us to Complete the statements to prove that line AB ⩭ to line CD and line BC ⩭ to line AD.
In statement 4 .∠CAB is congruent to ∠ACD as AB is parallel to CD and ∠BCA is congruent to∠CAD as AD is parallel to BC and these are Alternate interior angles to the parallel lines .
In statement 5.m∠CAB =∠ACD and ∠BCA = ∠CAD as by property of parallel lines Alternate interior angles are equal.
