MathDB
circumcircle passes through the midpoint

Source: Czech-Polish-Slovak Match 2013 day 2 P3

September 29, 2017
geometrycircumcirclereflectionarc midpoint

Problem Statement

Let ABC{ABC} be a triangle inscribed in a circle. Point P{P} is the center of the arc BAC{BAC}. The circle with the diameter CP{CP} intersects the angle bisector of angle BAC{\angle BAC} at points K,L{K, L} (AK<AL){(|AK| <|AL|)}. Point M{M} is the reflection of L{L} with respect to line BC{BC}. Prove that the circumcircle of the triangle BKM{BKM} passes through the center of the segment BC{BC} .