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MathNet 2014 Question 3

Math Olympiad Vault · MathNet 2014

Question 3

In triangle $ABC$, let $D\in BC$ with $AD$ the internal bisector of $\angle BAC$, and let $M$ be the midpoint of $AD$. Circle $\omega_1$ with diameter $AC$ intersects $BM$ at $E$, and circle $\omega_2$ with diameter $AB$ intersects $CM$ at $F$. Prove that $B,E,F,C$ are concyclic.

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