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MathNet 2024-part-03 — 168 problems (EN–VI) Question 146

Math Olympiad Vault · MathNet 2024-part-03 — 168 problems (EN–VI)

Question 146

Let $\omega$ be the circumcircle of $ABC$ where $AB \neq AC$, and let $M$ be the midpoint of side $BC$. Tangent lines drawn at points $B$ and $C$ of circle $\omega$ intersect at point $T$. The circumcircle of triangle $AMT$ intersects line $BC$ again at point $N$. Let $S$ be the midpoint of $NT$. Prove that $SA$ is tangent to the circle $\omega$.

(Gerelkhuu Erdenetugs)