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MathNet 2024-part-02 — 168 problems (EN–VI) Question 2

Math Olympiad Vault · MathNet 2024-part-02 — 168 problems (EN–VI)

Question 2

Let $ABC$ be a triangle and $D$ a point on its side $BC$. Points $E, F$ lie on the lines $AB, AC$ beyond vertices $B, C$, respectively, such that $BE = BD$ and $CF = CD$. Let $P$ be a point such that $D$ is the incenter of triangle $PEF$. Prove that $P$ lies inside the circumcircle $Ω$ of triangle $ABC$ or on it. (Josef Tkadlec, Czech Republic)