Find the circumradius of triangle
Source: Sharygin contest. The final raund. 2008. Grade 9. Second day. Problem 7
August 31, 2008
geometrycircumcircleparallelogramgeometric transformationreflectiongeometry unsolved
Problem Statement
(A.Zaslavsky) The circumradius of triangle is equal to . Another circle with the same radius passes through the orthocenter of this triangle and intersect its circumcirle in points , . Point is the fourth vertex of parallelogram . Find the circumradius of triangle .