You need to come up with the following notation to the side of the cube such that:

x = side of cube

You need to remember the formula that gives the volume of the cube:

`V(x) = x^3`

You need to differentiate the function of volume with respect to x such that:

`(dV(x))/(dx) = (d(x^3))/(dx)`

`dV = 3x^2 dx`

The problem provides the information that the length of the side of cube is of 18 inches and the error is of 0.005 inches such that:

`dV = 3*18^2*0.005 = 4.86`

**Hence, evaluating the approximate error in computing the volume of the cube yields `dV = 4.86` .**