MathDB
Geometry

Source: All Russian Grade 9 Day 2 P 3

December 12, 2015
geometrycircumcircle

Problem Statement

An acute-angled ABC (AB<AC)ABC \ (AB<AC) is inscribed into a circle ω\omega. Let MM be the centroid of ABCABC, and let AHAH be an altitude of this triangle. A ray MHMH meets ω\omega at AA'. Prove that the circumcircle of the triangle AHBA'HB is tangent to ABAB. (A.I. Golovanov , A.Yakubov)