Question

Find volume of cube whose diagonal is 3.6m

Answer 1

If that is the body diagonal, then
$x \sqrt{3} = 3.6 \\ x = 2.07 \\ volume = {x}^{ 3} \\ = {2.07}^{3} \\ 8.978 {m}^{3}$
If that's a face diagonal, then
$x \sqrt{2} = 3.6 \\ x = 2.545 \\ volume = {x}^{3} \\ = {2.545}^{ 3} \\ 16.49 {m}^{3}$