Problem

Source: 2018 All-Ukrainian Correspondence MO, grades 5-12 p9

Tags: geometry, Circumcenter, orthocenter, Ukraine Correspondence



Let $ABC$ be an acute-angled triangle in which $AB <AC$. On the side $BC$ mark a point $D$ such that $AD = AB$, and on the side $AB$ mark a point $E$ such that the segment $DE$ passes through the orthocenter of triangle $ABC$. Prove that the center of the circumcircle of triangle $ADE$ lies on the segment $AC$.