Question 33
$ABC$ and $A'B'C'$ are equilateral triangles and $ABC$ and $A'B'C'$ have the same sense (both clockwise or both counter-clockwise). Take an arbitrary point $O$ and points $P$, $Q$, $R$ so that $OP$ is equal and parallel to $AA'$, $OQ$ is equal and parallel to $BB'$, and $OR$ is equal and parallel to $CC'$. Show that $PQR$ is equilateral.