Question

A medallion of a tetrahedron: ABCD is a segment from one vertex (say A) of a tetrahedron to the centroid of the opposite face (triangle BCD). (Recall that the centroid of a triangle is the point of concurrency of the medians of the triangle.) Prove that any plane passing through a median of a tetrahedron and containing a second vertex of the tetrahedron bisects the volume of the tetrahedron.

Answer 1