To figure out the volume, visualize the box already folded.
In this figure, The cell address A2 is used to represent the size of the corner
cut. Then the side length remaining after the corner cut from a 3 ft x 3 ft
sheet of cardboard can be computed in cell C2 by:
= 3 - 2*A2
The volume, computed in cell B2 is:
= A2*C2*C2
After these computations are done in row 2, they can be repeated for other corner cut values in the subsequent rows. The largest volume can be found from the table or from a graph of the data.
What happens to the data for corner cuts greater than 1.5? What does this mean physically?