Problem

Source: 2024 RELSMO 2

Tags: geometry, circumcircle



In $\triangle ABC$ let $D$ and $E$ be points on $AB$ and $AC$ respectively. The circumcircle of $\triangle CDE$ meets $AB$ again at $F$, and the circumcircle of $\triangle ACD$ meets $BC$ again at $G$. Show that if the circumcircles of $DFG$ and $ADE$ meet at $H$, then the three lines $AG$, $BE$, and $DH$ concur. Proposed by Oron Wang inspired by Tiger Zhang