The rectangle is 4 cm wide and 14 cm long. Find the area of a square with the same perimeter.

Perimeter (P) is equal to the sum of all sides of the rectangle or twice the sum of the length and width, therefore:

P = 4 + 4 + 14 + 14 = 2 * (4 + 14) = 2 * 18 = 36 cm.

A square is a rectangle in which all sides are equal.

So the length of one side of a square with the same perimeter will be equal to:

36/4 = 9 cm.

The area (S) of a rectangle is equal to the product of its width and length, but the length of the square is equal to the width, therefore the area of the square is equal to its side in the square:

S = 9 ^ 2 = 81 cm2.