Answer:
The following angles are 45 degrees: SPT, QPT, PQT, RQT, QRT, SRT, RST, PST.
The following angles are 90 degrees: STP, PTQ, QTR, RTS
Explanation:
Notice that it is a square. Since it is a square, any diagonal line drawn from a corner to the opposite corner will bisect the angle at both corners. Since in a square each angle at each corner is 90 degrees, we know that the angles listed above are 45 degrees.
There are multiple ways to arrive at the conclusion that angles STP, PTQ, QTR, RTS are all 90 degrees. The easiest way to arrive at that answer is looking at each triangle. Notice how the square is divided into 4 triangles. Each triangle contains two 45 degree angles. Since the internal angles of each triangle must sum to 180 degrees, this means the last angle is 90 degrees.