IMO 2023 Shortlist G3

Let ABCD be a cyclic quadrilateral with =BAD ă =ADC. Let M be the midpoint of the arc CD not containing A. Suppose there...

IMO 2023 Shortlist G3

Category: Geometry

Problem

Let ABCD be a cyclic quadrilateral with =BAD ă =ADC. Let M be the midpoint of the arc CD not containing A. Suppose there is a point P inside ABCD such that =ADB “ =CPD and =ADP “ =PCB. Prove that lines AD,PM,BC are concurrent. (Slovakia)