ISL 2018 G4
A point is chosen inside a triangle . Let , and be the reflections of in , and , respectively. Let be the circumcircle of the triangle . The lines , and meet again at , and , respectively. Prove that the lines , and are concurrent on . (Mongolia)
Dataset text NuminaMath olympiads. Quoted with source.
Official text: IMO 2018 Shortlist booklet, page 8.
Solutions
Official solution Solution 1 by the IMO Problem Selection Committee
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