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MathNet 2023-part-05 — 191 problems (EN–VI) Question 150

Math Olympiad Vault · MathNet 2023-part-05 — 191 problems (EN–VI)

Question 150

Let $ABC$ be an acute, non-isosceles triangle. A circle $(O)$ passes through $B$, $C$ and meets $AB$, $AC$ at $D$, $E$. Lines $BE$, $CD$ meet at $I$. Denote $M$, $N$ as midpoints of $BE$, $CD$ and $MN$ meets $AB$, $AC$ at $P$, $Q$. Prove that $(OI)$ is tangent to $(APQ)$.