Maths Olympiad Prep

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, 2016

Geometry Difficulty 7.0 National Olympiad, round 2 Prove it Hungary

On the circumcircle of the scalene triangle ABCABC, let A0A_0, B0B_0, and C0C_0 be the midpoints of the arcs BACBAC, CBACBA and ACBACB, respectively. Denote by A1A_1, B1B_1 and C1C_1 the Feuerbach points of the triangles AB0C0AB_0C_0, BC0A0BC_0A_0 and CA0B0CA_0B_0, respectively. Show that the triangles A0B0C0A_0B_0C_0 and A1B1C1A_1B_1C_1 are similar.
Russian problem
(5 pont)

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