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Moldova JTST 2019 P7

Source:

April 19, 2019
geometry

Problem Statement

Point HH is the orthocenter of the acute triangle ΔABC\Delta ABC and point KK,situated on the line (BC)(BC), is the foot of the perpendicular from point AA .The circle Ω\Omega passes through points AA and KK ,intersecting the sides (AB)(AB) and (AC)(AC) in points MM and NN .The line that passes through point AA and is parallel with BCBC intersects again the circumcircles of triangles ΔAHM\Delta AHM and ΔAHN\Delta AHN in points XX and YY.Prove that XY=BCXY =BC.