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BALKAN-SL 2021 G1

Let ABCA B C be a triangle with AB<AC<BCA B<A C<B C. On the side BCB C we consider points DD and EE such that BA=BDB A=B D and CE=CAC E=C A. Let KK be the circumcenter of triangle ADEA D E and let F,GF, G be the points of intersection of the lines AD,KCA D, K C and AE,KBA E, K B respectively. Let ω1\omega_{1} be the circumcircle of triangle KDE,ω2K D E, \omega_{2} the circle with center FF and radius FEF E, and c3c_{3} the circle with center GG and radius GDG D.

Prove that ω1,ω2\omega_{1}, \omega_{2} and ω3\omega_{3} pass through the same point and that this point of intersection lies on the line AKA K.

Proposed by Greece

Dataset text NuminaMath olympiads. Quoted with source.

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