MathDB
Two tetrahedra and octahedra - Paenza 2010

Source:

August 27, 2010
geometry3D geometrytetrahedronoctahedronanalytic geometrygeometry unsolved

Problem Statement

In space are given two tetrahedra with the same barycenter such that one of them contains the other. For each tetrahedron, we consider the octahedron whose vertices are the midpoints of the tetrahedron's edges. Prove that one of this octahedra contains the other.