In article <3648DB75.6BF6@world.std.com>, firstname.lastname@example.org says... > Just step back and think about that. If two triangles are congruent, > that means they have the same shape. In fact, you must have proved a > theorem which says that if two triangles are congruent (or even > similar), then their corresponding angles are equal. And isn't that what > you are trying to prove? >
I think I get what you are saying. The next step would be to prove that the triangles are congruent. From their you can establish that Angle PTR corresponds to Angle QTR. If this is correct then I'm at a lost to find a suitable theorem or postulate for this.