Answer:
Hey there!
Triangle PQT and RQT are congruent by AAS. AAS means that one side is congruent, and two angles are congruent.
Since these triangles share one side, then the side is congruent.
PR is a straight line, so if angle Q is 90 degrees, then the supplementary angle is also 90 degrees.
Finally, the diagram shows that angles R and P are congruent to each other.
Hope this helps :)