ISL 2015 G6
Let be an acute triangle with , and let be its circumcircle. Let , , and be the orthocenter of the triangle, the midpoint of , and the foot of the altitude from , respectively. Let and be the two points on that satisfy and . Prove that the circumcircles of the triangles and are tangent to each other. (Ukraine)
Dataset text NuminaMath olympiads. Quoted with source.
Official text: IMO 2015 Shortlist booklet, page 7.
Solutions
Official solution Solution 1 by the IMO Problem Selection Committee
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