Final answer:
The correct postulate to prove that triangle QPR ≅ triangle PSR is the SSS (side-side-side) postulate.
Step-by-step explanation:
The correct postulate to prove that triangle QPR ≅ triangle PSR is the SSS (side-side-side) postulate.
The SSS postulate states that if the lengths of the three sides of one triangle are congruent to the lengths of the three sides of another triangle, then the two triangles are congruent.
In this case, if we can show that the lengths of sides QP, QR, and PR are congruent to the lengths of sides PS, SR, and PR respectively, then we can prove that triangle QPR ≅ triangle PSR using the SSS postulate.