In ΔPQR
PR>PQ ....(Given )
∴∠PQR>∠PRQ (Angle in the opposite of the longer side is greater) .............................(1)
In ΔPQS and ΔRPS
∠PQR=∠PQS=180−(∠PSQ+∠QPS)
∠PRQ=∠PRS=180−(∠PSR+∠RPS)
Given PS is bisector of ∠QPR
Then ∠QPS=∠RPS ...........................(2)
∠PQR>∠PRQ (As per (1))
∴180−(∠PSQ+∠QPS)>180−(∠PSR+∠RPS) (∠QPS=∠PRQ)
⇒∠PSR>∠PSQ [henceproved]