Answer:
[tex]84\text{ in}^2[/tex].
Step-by-step explanation:
We have been given that Mrs. Chen's students are making and decorating gift boxes for a nursing home. The boxes are 7 inches wide, 7 inches long, and 7 inches high. We are asked to find the amount of cardboard that is needed for each box.
We will use surface area of cuboid formula to solve our given problem.
[tex]SA=2(lw+lh+hw)[/tex], where,
l = Length,
w = Width,
h = Height
[tex]SA=2(7\text{ in}\cdot7\text{ in} +7\text{ in}\cdot7\text{ in}+7\text{ in}\cdot7\text{ in})[/tex]
[tex]SA=2(14\text{ in}^2+14\text{ in}^2+14\text{ in}^2)[/tex]
[tex]SA=2(42\text{ in}^2)[/tex]
[tex]SA=84\text{ in}^2[/tex]
Therefore, Mrs Chen needs 84 square inches of cardboard.