circumcircle and altitudes! CMO 2015 P4
Source: canadian mathematical olympiad
April 24, 2015
geometrycircumcircleCanada2014National Olympiads
Problem Statement
Let be an acute-angled triangle with circumcenter . Let be a circle with center on the altitude from in , passing through vertex and points and on sides and . Assume that
Prove that is tangent to the circumcircle of triangle .