Cyclic Quad. with Perp. Diagonals [Austria Regional 2017, P2]
Source: Austrian Mathematics Olympiad Regional Competition (Qualifying Round) 2017, Problem 2
February 28, 2018
geometry
Problem Statement
Let be a cyclic quadrilateral with perpendicular diagonals and circumcenter . Let be the line obtained by reflection of the diagonal along the angle bisector of . Prove that the point lies on the line .Proposed by Theresia Eisenkölbl