Question 1001551
The diagonal of a cube of side s is given by
{{{d = s*sqrt(3)}}}

The surface area is
SA = 6*s^2 = 6*(d/sqrt(3))^2
SA = 2d^2

The volume is given by
V = s^3 = {{{(d/sqrt(3))^3}}}
V = {{{d^3/(3*sqrt(3))}}} or
V = {{{d^3*sqrt(3) / 9}}}