Question 61
Let $ABCD$ be a cyclic quadrilateral. The lines $AD$, $BC$ meet at $P$; $AB$, $CD$ at $Q$; and $AC$, $BD$ at $R$. The perpendicular bisectors of $AB$, respectively $BC$, meet $PR$ at $X$, respectively $QR$ at $Y$. Prove that $XY$ passes through $B$.