Chord PQ of a circle subtends angles at two points R and S on the same segment. It is given that ∠PRQ=40∘ and ∠QPS=64∘. Answer the following.
a. (i) Calculate ∠PSQ.
b. (ii) Find ∠PQS.
c. (iii) Determine the three interior angles of △PQS and verify that their sum is 180∘.