Question 125
Let $ABC$ be an acute triangle with an intersection point $H$ and let $M$ and $N$ be two points on $BC$ such that $\overrightarrow{MN}=\overrightarrow{BC}$. Let $P$ and $Q$ be the projections of $M$ and $N$ onto $AC$ and $AB$, respectively. Show that $APHQ$ is a chord quadrilateral.