ASU 447 All Soviet Union MO 1987 3 lines // triangle sides, concyclic wanted
Source:
August 7, 2019
geometryConcyclicparallel
Problem Statement
Three lines are drawn parallel to the sides of the triangles in the opposite to the vertex, not belonging to the side, part of the plane. The distance from each side to the corresponding line equals the length of the side. Prove that six intersection points of those lines with the continuations of the sides are situated on one circumference.