Proof. Notice that because of the Radical Axis theorem, the quadrilateral $BCMN$ is cyclic. It follows that $\angle{BCM}=\angle{BNM}$. Observe that $\angle{MAC}+\angle{BCM}=90^\circ$ ($\triangle{ACM}$ is a right triangle). It turns out that $AMND$ is cyclic. Indeed, $\angle{MAD}+\angle{MNB}+\angle{BND}=180^\circ$.
No hay comentarios:
Publicar un comentario