Equality for acute triangle, and tangents of circumcircle
Source: Problem 6 of Russian Regional Olympiad 2011, grade 11
September 1, 2011
geometrycircumcircleperpendicular bisectorgeometry proposed
Problem Statement
is the circumcirle of an acute triangle . The tangent line passing through intersects the tangent lines passing through points and at points and , respectively. The line parallel to through and the line parallel to through intersect at point . Prove that .
(Author: P. Kozhevnikov)