We have to know which angle of triangle PQR is the right angle. Is the right angle PQR, QRP, or RPQ???? Also we have to know which angle of right triangle RST is right angle. Is the right angle RST, STR, or SRT???? Also where is point T??? Is T a point on PR? Or is S a point on PR??? Sorry, you have not given us enough information. Please repost telling us more. Edwin