5

Part of 1995 ITAMO

Problems(1)

tangent circles in space with same tangents at common point lie on sphere

Source: 1995 ITAMO p5

Two non-coplanar circles in space are tangent at a point and have the same tangents at this point. Show that both circles lie on some sphere.

3D geometrygeometryspherecirclestangent circlesTangents