Question 140
The points $A$, $B$, $P$, $Q$ are collinear, and $ABCD$ is a parallelogram. The lines $PD$ and $BC$ meet at $E$. The lines $QC$ and $AD$ meet at $F$. The lines $PF$ and $BC$ meet at $H$. The lines $QE$ and $AD$ meet at $G$.
Prove that $GH$ is parallel to $AB$.
Prove that $GH$ is parallel to $AB$.