concurrent circumcircles related to 3 cyclic quadrilaterals, circumcenter
Source: Sharygin 2011 Final 10.7
March 31, 2019
geometrycyclic quadrilateralCircumcenterconcurrentcirclesaltitudescircumcircle
Problem Statement
Point is the circumcenter of acute-angled triangle , points are the bases of its altitudes. Points lying on lines respectively are such that quadrilaterals are cyclic. Prove that the circumcircles of triangles have a common point.