Marley bakes a rectangular cake that is 9 inches wide, 13 inches long and 2 inches high. She removes the cake from the pan to frost it. How many square inches of frosting does she need?
HINT: The bottom of the cake is not iced. You will use S=Ph+B because the bottom of the cake is not iced.
First, we need to find the surface area of the four sides of the cake that need frosting.
The two shorter sides have an area of 9 inches * 2 inches = 18 square inches each.
The two longer sides have an area of 13 inches * 2 inches = 26 square inches each.
Adding them all together:
18 sq in + 18 sq in + 26 sq in + 26 sq in = 88 square inches
So Marley will need 88 square inches of frosting to cover the four sides of the cake.