Croatian mathematical olympiad, day 2 problem 3
Source:
April 10, 2011
geometrycircumcircleperpendicular bisectorprojective geometrypower of a pointradical axisgeometry unsolved
Problem Statement
Let and be the points on the semicircle with diameter . Denote intersection of and as and let be the point such that is on segment and line is perpendicular to . If is the intersection of perpendicular bisector of an and is a point on such that angles and are equal. Prove that is perpendicular to .