Question 112
A semicircle $\Omega$ with diameter $AD$ is given. Let $O$ be the midpoint of $AD$. Let $B$ be a point on $\Omega$ and $M$ be a point on the segment $OA$ such that $2AM = BM$. Let the midpoint of segment $BM$ be $N$ and the midpoint of segment $BN$ be $K$. On the semicircle $\Omega$, the point $C$ is taken so that $OC$ is parallel to $MB$. Prove that $ON = KC$.
(Khulan Tumenbayar)
(Khulan Tumenbayar)