Question 111
In cyclic quadrilateral $A B C D$, $E$ is the intersection of the diagonals. A line through $E$, different from $A C$ and $B D$, intersects $A B$ at $P$ and $B C$ at $Q$. The circle that is tangent to $P Q$ at $E$ and also passes through $D$ intersects the circumcircle of $A B C D$ again at point $R$. Prove that $B, P, R$ and $Q$ lie on a circle.
