So if we know the volume of a cube is given by V = x ^ 3, and V = 3 3/8, then 3 3/8 = x ^ 3
So here we now know we have to find the, err, triple square root or something of 3.
Since square root is just x ^ 1/2, then we know that it would be x ^ 1/3 to figure out this problem.
So just replace x with 3 3/8, to get 1.5.
So the answer you're looking for is 1.5.