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MathNet 2023-part-03 — 191 problems (EN–VI) Question 42

Math Olympiad Vault · MathNet 2023-part-03 — 191 problems (EN–VI)

Question 42

Triangle $ABC$ is an acute-angled triangle with orthocenter $H$. Point $P$ is inside triangle $BHC$ such that $3\angle HBC = \angle HPC$ and $3\angle HCB = \angle HPB$. Denote by $X$ and $Y$ the reflections of $P$ with respect to $BH$ and $CH$, respectively. If $S$ is the circumcenter of triangle $AXY$, prove that $\angle CAP = \angle BAS$.