ABCD is a a parallelogram. A circle passing through D , A,B cuts BC in P Prove that DC = DP Share with your friends Share 4 Global Expert answered this ∠DAB=90° and ∠DPB=90° Angle in the semicircle is 90°∠DAB+ ∠DPB=180° Therefore, ABPD is a cyclic quadrilateral.Now, suppose that ∠DAB=θ ∠DAB+∠DPB=180° (ABPD is a cyclic quadrialteral)⇒∠DPB=180°-θ∠DAB=∠DCB=θ (Opposite angles of a parallelogram are equal)∠DPC=180°-∠DPB (Linnear pair)⇒∠DPC=180°-180°+θ⇒∠DPC=θHence, ∠DPC=∠DCP=θi.e., DC=DP (Sides opposite to equal angle) -4 View Full Answer