BALKAN-SL 2016 G3
Given that is a triangle where . On the half-lines and we take points and respectively such that . Let and be the mid-points of the segments and respectively and and be the circumcircles of the triangles and respectively. We assume that cuts and at the points and respectively and that is the point of intersection of and . If the parallel line from to cuts the line at and the perpendicular from to the line cuts at the point , prove that is the orthocenter of the triangle .
Dataset text NuminaMath olympiads. Quoted with source.
Solutions
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