Tetrahedron and sphere - TT 2009 Senior-A3
Source:
September 3, 2010
geometry3D geometrytetrahedronspheregeometry unsolved
Problem Statement
Every edge of a tetrahedron is tangent to a given sphere. Prove that the three line segments joining the points of tangency of the three pairs of opposite edges of the tetrahedron are concurrent.(7 points)