Problem

Source: 2012 Oral Moscow Geometry Olympiad grades 10-11 p3

Tags: altitude, orthocenter, concurrency, concurrent, geometry



$H$ is the intersection point of the heights $AA'$ and $BB'$ of the acute-angled triangle $ABC$. A straight line, perpendicular to $AB$, intersects these heights at points $D$ and $E$, and side $AB$ at point $P$. Prove that the orthocenter of the triangle $DEH$ lies on segment $CP$.