What is the area of a rectangle whose perimeter is 18?

Answer 1

The area of a rectangle with a perimeter of 18 can be anything

from 20.25 down to almost zero.

If it's a square:

Each side is 1/4 of 18 = 4.5

Perimeter = 4 x 4.5 = 18

Area = (4.5)2 = 20.25

If it's a long, skinny rectangle, such as 0.1 wide x 8.9 long:

Perimeter = 0.1 + 8.9 + 0.1 + 8.9 = 18

Area = 0.1 x 8.9 = 0.89

The longer and skinnier it is, the less area it has.