To solve this problem you must apply the proccedure showm below:
1. As you can see in the figure attached, the square piece of cardboard measures 14 inches on each side and the sides of each congruent squares of each corner of the cardboard is 4 inches. Therefore, you have that the area of the cardboard you will use to build the box is:
At=A1-A2
At is the area you will use to build the box.
A1 is the original area of the the square piece of cardboard.
A2 is the the area of the congruent squares.
2. Then, you have:
A1=(14 inches)²
A1=196 inches²
A2=(4 inches)²x4 squares
A2=64 inches²
At=196 inches²-64 inches²
At=132 inches²
The answer is: 132 inches²