MathNet 2017-part-02 — 176 problems (EN–VI) Question 34

Let $ABC$ be an acute-angled triangle. The tangents at $A$ and $B$ to its circumcircle intersect at $M$. The line through $M$ parallel to the side $BC$ intersects the side $CA$ at point $N$. Prove that $|BN| = |CN|$ holds.