circle $W_{1}$ and circle $W_{2}$ intersect at $P$,$Q$ draw a line $\overline{AB}$ thought $P$ intersect $W_{1}$ and $W_{2}$ at $A$ and $B$ respectively let $C$,$D$ are the midpoint of $arc(AQ)$ and $arc(BQ)$ respectively if $M$ is a midpoint of $\overline{AB}$ prove that $\hat{CMD}=90^๐$
