We have,
Given that, ∠PQR=∠PRQ
Let ∠PQR=x then ∠PRQ=x
Now, we know that
∠PQS+∠PQR=180o
∠PQS=180o−∠PQR
∠PQS=180o−x.......(1)
Also, we can say that,
∠PRT+∠PRQ=180o
∠PRT=180o−∠PRQ
∠PRT=180o−x......(2)
By equation (01 and (2) to and we get,
∠PQS=∠PRT
Hence proved.