On a 3-Dimensional Isoperimetric Problem
Magelone Kömhoff · Canadian Mathematical Bulletin · 1970
Let L(P) denote the total edge length and A(P) the total surface area of a three-dimensional convex polyhedron P. In [5] it was shown that if P belongs to the set of all polyhedra with triangular faces then for all with equality if and only if is a regular tetrahedron. It is not difficult to establish the inequality