A square in sheet of side 12 inches is converted into a box with open top in the following steps. The sheet is placed horizontally. Then, equal-sized squares, each of side $x$ inches, are cut from the four corners of the sheet. Finally, the four resulting sides are bent vertically upwards in the shape of a box. If $x$ is an integer, then what value of $x$ maximizes the volume of the box?
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Use optimization techniques such as differentiation to maximize or minimize quantities like volume in geometric problems.
The volume $V$ of the box formed is given by the formula:
\[
V(x) = x(12 - 2x)^2
\]
To maximize the volume, we differentiate $V(x)$ with respect to $x$ and set it equal to zero to find the critical points. After solving, we find that the value of $x$ that maximizes the volume is $3.1$.