Hard geometry
Source: Serbia 2008
April 13, 2008
geometrycircumcirclegeometric transformationhomothetysimilar trianglesgeometry unsolved
Problem Statement
Triangle is given. Points i are on line such that D \minus{} A \minus{} B \minus{} E, AD \equal{} AC and BE \equal{} BC. Bisector of internal angles at and intersect at and , and circumcircle of at and . Line which connects with center of circumcircle of and line which connects and center of circumcircle of intersect at . Prove that .