ISL 2015 G2
Let be a triangle inscribed into a circle with center . A circle with center meets the side at points and such that lies between and . Moreover, let and be the common points of and . We assume that lies on the arc of not containing , and lies on the arc of not containing . The circumcircles of the triangles and meet the sides and again at and , respectively. Suppose that the lines and are distinct and intersect at . Prove that the points , and are collinear. (Greece)
Dataset text NuminaMath olympiads. Quoted with source.
Solutions
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