C-03-Q074mediumsingle_mcq△PQR\triangle PQR△PQR এ ∠PQR=90°\angle PQR = 90°∠PQR=90° এবং QF⊥PRQF \perp PRQF⊥PR হলে QF2=?QF^2 = ?QF2=?aPF+RFPF + RFPF+RFbPF⋅RFPF \cdot RFPF⋅RFcPF2+RF2PF^2 + RF^2PF2+RF2dPF2−RF2PF^2 - RF^2PF2−RF2