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MathNet 2015-part-05 — 191 problems (EN–VI) Question 68

Math Olympiad Vault · MathNet 2015-part-05 — 191 problems (EN–VI)

Question 68

Let $ABC$ be a triangle and $D$ a point on the side $BC$. Point $E$ is the symmetric of $D$ with respect to $AB$. Point $F$ is the symmetric of $E$ with respect to $AC$. Point $P$ is the intersection of line $DF$ with line $AC$. Prove that the quadrilateral $AEDP$ is cyclic.