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Some geometry

Source: Moscow Olympiad 2018, Grade 10, P3

July 13, 2018
geometrycircumcircle

Problem Statement

OO is circumcircle and AHAH is the altitude of ABC\triangle ABC. PP is the point on line OCOC such that APOCAP \perp OC. Prove, that midpoint of ABAB lies on the line HPHP.