To prove <QPR = <QRP we have to prove ΔPTR ≅ ΔRSP
Let T be the mid point of PQ and S be the mid point of QR
line joining T and S is TS parallel to PR
Triangle PTR and triangle RSP have same base, one side equal and between same parallel are congruent.
Therefore ΔPTR ≅ ΔRSP by CPCTC <QPR = <QRP
So we can cnclude that PQR is an isosceles triangle.
