What is the area of a 21 cm wide rectangular sheet of paper with a perimeter of 102 cm?

In order to find what is equal to the area of a rectangular sheet of paper 21 cm wide, and the perimeter of which is 102 cm.

Let’s first find the length of the rectangle.

To do this, recall the formula for finding the perimeter of a rectangle.

P = 2 (a + b);

Substitute the known values and calculate:

2 (21 + x) = 102;

21 + x = 102: 2;

21 + x = 51;

x = 51-21;

x = 30 cm rectangle length.

We found the sides of the rectangle, now we are looking for the area of the rectangle using the formula:

S = a * b = 30 * 21 = 630 cm2.