Copyright © University of Cambridge. All rights reserved.

'A Mean Tetrahedron' printed from http://nrich.maths.org/

Show menu

A tetrahedron has 4 vertices, 6 edges and 4 faces. Can you number them 1 to 14 in such a way that the number on each edge is the mean of the two numbers at the vertices joined by that edge and also the mean of the two numbers on the faces it separates?