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 QMN and MNR are congruent?

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 QMN and MNR are congruent?

anonymous · Answer

If two lines intersect, the vertical angles are complementary.
		If two lines intersect, the corresponding angles are supplementary.
		If two angles measure the same, then the angles are supplementary.
		If two angles are alternate interior angles, their measures are the same.

anonymous · Answer

the last statement