PQ and RS are two lines that intersect at point T, as shown below:
(PIC BELOW)
Which fact is used to prove that angle PTR is always equal to angle STQ?
A) Lines PQ and RS have a fixed length.
B) Lines PQ and RS intersect at right angles.
C) If two angles are equal to the same measure, then the angles are congruent.
D) If two angles are equal to the same measure, then the angles are supplementary
