(In reply to
i c it this way by Ady TZIDON)
Right angled triangles can be made not only restricted to one side, but also using as legs one edge and a diagonal of an adjacent side to the two sides that form that edge (not a diagonal of one of the two sides themselves). The hypotenuse is then a main diagonal of the cube. The sides are in ratio 1:sqrt(2):sqrt(3)
There are 12 edges, and two choices of diagonal for each, so another 24/56 or 3/7 of the cases are like this, leaving only 1/7 for acute triangles.

Posted by Charlie
on 20041205 15:15:44 