If Sis any point on the base QR produced of an isosceles triangle PQR. prove that PQPR

Dear Yashita,
since PQR is an isosceles triangle, PQ = PR and QR is the base of the triangle.
figure to the question is as given below:

your question is incomplete as what is required to prove , is missing from the question.
please again go through the question and do get back to us.