Using only the vertices of a regular octahedron as the corners, how many equilateral triangles in total is it possible to make?
(In reply to
My guess by tomarken)
Agree. At each of the 6 vertices, four of the others are the same distance and form only faces of the octahedron (or isosceles triangles across the square crosssection). The remaining vertex is at a unique distance (for the given original vertex) and can't form an equilateral triangle.

Posted by Charlie
on 20140728 17:33:02 