From the question, we're told that the area of the cubic box is 96 square feet of wood, expressed thus;

Let's call the length of each edge x. But we know that formula for finding the area of a cube is;

So let's go ahead and equate the two equations and solve for x;
![\begin{gathered} 96=6x^2 \\ x^2=(96)/(6) \\ x^2=16 \\ x=\sqrt[]{16} \\ \therefore x=4ft \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/g6e5eownjdi67a4bwz2qtd4ccfi51jr9fo.png)
Therefore the length of each edge is 4ft.