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MathNet 2019-part-01 — 184 problems (EN–VI) Question 54

Math Olympiad Vault · MathNet 2019-part-01 — 184 problems (EN–VI)

Question 54

Given an acute triangle $ABC$, let $M$ be the midpoint of $BC$ and $H$ the orthocentre. Let $\Gamma$ be the circle with diameter $HM$, and let $X$, $Y$ be distinct points on $\Gamma$ such that $AX$, $AY$ are tangent to $\Gamma$. Prove that $BXYC$ is cyclic.