Euclid XII 3(a)
- Gaute Storli Nielsen
Euclid, book XII, proposition 3 (a). Let the four 3D-points A, B, C, D span a pyramid with triangular base, or a tetrahedron. Make sure the four points are not all coplanar. The three generated figures (in red) can be printed, cut and glued to make two prisms of equal volume, and a triangular pyramid. The two prisms and two copies of the pyramid can be used to build a larger pyramid similar to the original, but with all segment lengths doubled.