2019 Iberoamerican Mathematical Olympiad, P3
Source:
September 15, 2019
geometrycircumcircle
Problem Statement
Let be the circumcircle of triangle . The line parallel to passing through meets at (), and the line parallel to passing through intersects to (). Lines and meet at , and lines and meet at . Let be the midpoint of . Line meets at () and line at . Line intersects the circumcircle of triangle at (). If lines and meet each other at , show that lies on the line .