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MathNet 2024-part-01 — 168 problems (EN–VI) Question 20

Math Olympiad Vault · MathNet 2024-part-01 — 168 problems (EN–VI)

Question 20

Let $ABC$ be an acute triangle with orthocenter $H$. The circumcircle of the triangle $BHC$ intersects $AC$ a second time in point $P$ and $AB$ a second time in point $Q$.
Prove that $H$ is the circumcenter of the triangle $APQ$.