The perimeter of the rectangle is 100 cm, the length is 30 cm. The computational area of the rectangle.

The perimeter is the sum of all sides. For such a figure, it is determined by the formula:

P = 2a + 2b. Provided that this value is 100 cm, and length = 30 cm, first of all we find the width:

2b = P – 2а = 100 – 2 * 30 = 100 – 60 = 40. To find the second factor, divide the product by the first:

b = 40: 2 = 20 cm.

The area of the rectangle is calculated by the formula:

S = a * b = 30 * 20 = 600 cm².