In △PQR, side QR is produced to a point S. Prove that ∠PRS (the exterior angle) is equal to the sum of the interior opposite angles ∠PQR and ∠QPR.
Only the headings Given and To Prove are provided below. Complete the task that follows.
Given: △PQR with QR produced to S.
To Prove: ∠PRS=∠PQR+∠QPR.
Write a full paragraph proof under the headings Given, To Prove, Proof, and Conclusion. Explicitly cite every axiom, definition, or theorem used in each step of your reasoning.