Tangential Polyhedra
Source: Iran 3rd round 2009 - final exam problem 7
January 2, 2015
geometry3D geometryspheregeometry unsolved
Problem Statement
A sphere is inscribed in polyhedral . The faces of are coloured with black and white in a way that no two black faces share an edge.
Prove that the sum of surface of black faces is less than or equal to the sum of the surface of the white faces.Time allowed for this problem was 1 hour.