Quadrilateral BECD and triangle ABC have the same area
Source: Germany Bundeswettbewerb Mathematik 2001, Round 1, Problem 3
February 1, 2009
geometrycircumcircleparallelogramtrigonometrygeometry unsolved
Problem Statement
Let an acute triangle with circumcircle center The line intersects the circumcircle again in and the extension of the altitude from intersects the circle in Prove that the quadrilateral and the triangle have the same area.