MathDB
Vietnam NMO 1990_3

Source:

October 26, 2008
geometry3D geometrytetrahedrongeometry unsolved

Problem Statement

A tetrahedron is to be cut by three planes which form a parallelepiped whose three faces and all vertices lie on the surface of the tetrahedron. (a) Can this be done so that the volume of the parallelepiped is at least 940 \frac{9}{40} of the volume of the tetrahedron? (b) Determine the common point of the three planes if the volume of the parallelepiped is 1150 \frac{11}{50} of the volume of the tetrahedron.