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MathNet 2016-part-06 — 184 problems (EN–VI) Question 173

Math Olympiad Vault · MathNet 2016-part-06 — 184 problems (EN–VI)

Question 173

Let $AM$ be a median in an acute triangle $ABC$. Its extension intersect the circumcircle $w$ of $ABC$ at $P$. Let $AH_1$ be an altitude of $\triangle ABC$, $H$ - its orthocenter. The rays $MH$ and $PH_1$ intersect $w$ at $K$ and $T$ respectively. Prove that the circumcircle of $\triangle KTH_1$ is tangent to $BC$.

(Khilko Danylo)