Question

The figure below shows line PQ parallel to line RS. The parallel lines are cut by the transversal XY.

Which fact is used to prove that angles PMN and MNS are congruent?
All pairs of alternate interior angles have the same measure.

If two parallel lines are cut by a transversal, the corresponding angles are supplementary.

If two lines intersect, the vertical angles are supplementary.

All angles equal to the same measure are complementary.

Answer 1

@NaCl Can you help?

Answer 2

@FilthyMcNasty Help?

Answer 3

Late response, srry. But answer: All pairs of alternate interior angles have the same measure.