Question

What reason should kamal add to all of the question marks in order to completer the proof

Answer 1

Answer: The answers is alternate interior angles.

Step-by-step explanation:  First of all, the questions marks given in the figure are renamed in the attached figure as (a), (b), (c) and (d).

For (a): Since AC is parallel to A'C' and A'D is a transversal for these two parallel lines, so, ∠CDB' = ∠B'A'C', because these are alternate interior angles.

For (b): Since BC is parallel to B'C' and A'B' is a transversal, so ∠BEB' = ∠A'B'C', because these are alternate interior angles.

For (c): Since AB is parallel to A'B' and AD is a transversal, so ∠BAC = ∠CDB', because these are alternate interior angles.

For (d): Since AB is parallel to A'B' and BE is a transversal, so ∠ABC = ∠BEB', because these are alternate interior angles.

Thus, all the questions marks are the reasons that the given angles are equal because they are alternate interior angles.