Question

which statement is used to prove that angle PTR is always equal to angle STQ?

Lines PQ and RS do not have a fixed length.

Angle PTR and angle PTS are supplementary angles.

Lines PQ and RS intersect at an angle less than a right angle.

Angle PTR and angle PTS are complementary angles.

Answer 1

the answer:

first of all, the theorem says, vertical angles are congruent. that's why  Angle PTR and angle PTS are congruent.
according to the image, the true answer is Angle PTR and angle PTS are

complementary angles, that is because  mAngle PTR + m angle PTS are ≤90°