Question 21
G2 (RUS) IMO1. Two circles $G_1$ and $G_2$ intersect at $M$ and $N$. Let $AB$ be the line tangent to these circles at $A$ and $B$, respectively, such that $M$ lies closer to $AB$ than $N$. Let $CD$ be the line parallel to $AB$ and passing through $M$, with $C$ on $G_1$ and $D$ on $G_2$. Lines $AC$ and $BD$ meet at $E$; lines $AN$ and $CD$ meet at $P$; lines $BN$ and $CD$ meet at $Q$. Show that $EP=EQ$.