MathDB
then the polyhedron cannot have an inscribed sphere

Source: 1985 Polish MO Finals p6

January 21, 2020
3D geometrygeometrypolyhedronsphereinscribed

Problem Statement

There is a convex polyhedron with kk faces. Show that if more than k/2k/2 of the faces are such that no two have a common edge, then the polyhedron cannot have an inscribed sphere.