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MathNet 2023-part-03 — 191 problems (EN–VI) Question 59

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

Question 59

In the triangle $ABC$, variable points $D$, $E$, $F$ are on the sides $BC$, $CA$, $AB$ respectively such that the triangle $DFE$ is similar to the triangle $ABC$ in the same order as written. Circumcircles of $BDF$ and $CDE$ intersect the circumcircle of $ABC$ at $P$ and $Q$, respectively, for the second time. Prove that the circumcircle of $DPQ$ passes through a fixed point.