MathDB
concyclic wanted

Source: 1977 Hungary - Kürschák Competition p2

October 15, 2022
geometryConcyclic

Problem Statement

ABCABC is a triangle with orthocenter HH. The median from AA meets the circumcircle again at A1A_1, and A2A_2 is the reflection of A1A_1 in the midpoint of BCBC. The pointsB2 B_2 and C2C_2 are defined similarly. Show that HH, A2A_2, B2B_2 and C2C_2 lie on a circle. https://cdn.artofproblemsolving.com/attachments/f/1/192d14a0a7a9aa9ac7b38763e6ea6a4a95be55.png