MathDB
<BLC=2<BAC wanted, symmedian and circumcircle related

Source: Champions Tournament (Ukraine) - Турнір чемпіонів - 2005 Seniors p2

September 6, 2020
geometrycircumcirclesymmediananglesequal anglesChampions Tournament

Problem Statement

Given a triangle ABCABC, the line passing through the vertex AA symmetric to the median AMAM wrt the line containing the bisector of the angle BAC\angle BAC intersects the circle circumscribed around the triangle ABCABC at points AA and KK. Let LL be the midpoint of the segment AKAK. Prove that BLC=2BAC\angle BLC=2\angle BAC.