MathDB
three circles in space

Source: Eotvos 1937 p2

September 10, 2024
geometry3D geometrytangent circles

Problem Statement

Two circles in space are said to be tangent to each other if they have a corni-non tangent at the same point of tangency. Assume that there are three circles in space which are mutually tangent at three distinct points. Prove that they either alI lie in a plane or all lie on a sphere.