The length of the rectangle is 4 cm, what is its area if the perimeter is 10 cm.

It is known that the length of a rectangle is 4 centimeters.

It is required to calculate what the area of this rectangle is, provided that its perimeter is 10 cm.

The perimeter of a rectangle is twice the sum of its length and width.

P = 2 * (a + b).

Therefore, to calculate its width, it is necessary to find the difference between the half-perimeter and the length.

b = P / 2 – a.

b = 10/2 – 4 = 5 – 4 = 1 cm.

To calculate the area of a rectangle, you need to multiply its length by width.

S = a * b.

S = 4 * 1 = 4 cm2.