Problem

Source: XII International Festival of Young Mathematicians Sozopol 2023, Theme for 10-12 grade

Tags: geometry



Given a triangle $ABC$ ($AC < BC$) with circumcircle $k$ and orthocenter $H$, let $W$ be any point on segment $CH$. The circle with diameter $CW$ intersects $k$ a second time at point $K$ and intersects sides $BC$ and $AC$ at points $M$ and $N$, respectively. The line $KW$ intersects segment $AB$ at point $L$. Prove that the circumcircle of triangle $MNL$ passes through a fixed point, independent of the choice of $W$.