tangent points of bases (circles) of 4 cones are concyclic
Source: Sharygin 2006 XI CR 26
August 26, 2019
geometrycone3D geometryConcyclictangent circles
Problem Statement
Four cones are given with a common vertex and the same generatrix, but with, generally speaking, different radii of the bases. Each of them is tangent to two others. Prove that the four tangent points of the circles of the bases of the cones lie on the same circle.