Question

Kelly has a rectangular fish aquarium that measures 18 inches long, 8 inches wide, and 12 inches tall.

a. What is the maximum amount of water the aquarium can hold?
b. If Kelly wanted to put a protective covering on the four glass walls of the aquarium, how big does the cover have to be?

Answer 1

a) The maximum amount of water the aquarium can hold is 1728 in³.

b) The cover has to be 624 in² big.

Explanation:

a) The maximum volume of water that the aquarium can have is the same as the volume of the aquarium:

V=L×W×H=18 in × 8 in × 12 in= 1728 in³

b) The protective covering is used on the four walls of the aquarium. We have to find the areas of the four walls:

One of them is given by the multiplication of the width and the height:

A₁= W×H= 8 in × 12 in=96 in²

The other area is given by the multiplication of the length and the height:

A₂= L×H= 18 in × 12 in= 216 in²

As the fish aquarium is rectangular the area of the walls is given by:

`A_T=2A_1+2A_2`=2×96 in²+2×216 in²=624 in²