X must be centre of circle,
∵ diagonals of a cyclic quadrilateral intersect at the centre of circle.
∴∠XPM=900(∵Tangent&normalareat900).and∴∠PXQ=∠RXQ=900.(∵SQ∥PM).∴∠RXS=900(SumofAnglesonastraightline=1800).Hence,In△RXSl△RXQ:⇒∠RXS=∠RXQ=900XR=XR(common)XS=XQ(Radius)∴△SRX≅△RXQ(byR.H.S.)∴∠SRX=∠XRQ.Hence,wecansaythatPRbisects∠QRS.Hence,proved.