MathDB
Geometry Mathley 8.3 concyclic

Source:

June 7, 2020
Concycliccircumcircleorthocentergeometry

Problem Statement

Let ABCABC be a scalene triangle, (O)(O) and HH be the circumcircle and its orthocenter. A line through AA is parallel to OHOH meets (O)(O) at KK. A line through KK is parallel to AHAH, intersecting (O)(O) again at LL. A line through LL parallel to OAOA meets OHOH at EE. Prove that B,C,O,EB,C,O,E are on the same circle.
Trần Quang Hùng
Back to ProblemsView on AoPS