ASA
SAS
SAS
sss
Gram crackers
Asa /sss
Well, this will depend on the length of the sides of the triangle for what postulate or theorem you will be using.
AAS (apex)
For this type of question the diagram that is with the question is needed to provide you an answer.
We cannot determine without seeing the data for PRS & QRS. My guess though would be ASA Though it could also be SSS
Pythagorean theorem
Yes, the corollary to one theorem can be used to prove another theorem.