Question

You have an aquarium in the shape of a rectangular prism. The base is 4 feet by 3 feet. The height is 2 feet. How many square feet of glass were used to build the aquarium? (The top of the aquarium is open.)

Answer 1

Since it is about only the outer part of the aquarium which is made of glasses we need to calculate the total surface area.

Surface area of the base = 4*3 = 12 square feet

Surface area of the shorter length of wall = 3*2 = 6 square feet
since it has another wall in opposite side. It has to be multiplied with 2.
6*2 = 12 square feet

Surface area of the longer length of wall = 4*2 = 8 square feet
since it has another wall in opposite side. It has to be multiplied with 2.
8*2 = 16 square feet

Therefore the total surface area that need to be covered with glasses
12+12+16 = 40 square feet