Number 3
To find the answer, we should mark what are given in the question.
The first one, ∠Q ≅ ∠T so the first proof is Angle (A)
The second one, go to the adjacent of ∠Q or ∠T. What are given in the question: PR ≅ SR, so the second proof is Side (S)
The third one, go to the adjacent of PR or SR. It's already proven that ∠PRQ and ∠SRT are ≅, so the third proofi is Angle (A)
The proof for number 3 is ASA
Number 4
To solve number 4, we go back to the previous number. It's proven that ΔPRQ ≅ ΔSRT. And the corresponding part of congruent triangle is congruent.
The proof for number 4 is CPCTC