One side of the rectangle by 3cm, the perimeter of the rectangle is 42cm, calculate the length of each side.

Let us denote by a the length of the shorter side of this rectangular quadrangle.

In the initial data for this task, it is reported that one of the sides of this rectangular quadrangle is 3 centimeters larger than the other, therefore, the length of the larger side of this quadrangle is x + 3 cm.

It is also known that the sum of the lengths of all four sides of a given quadrangle is equal to forty-two centimeters, therefore, we can draw up the following equation:

x + x + x + 3 + x + 3 = 42,

solving which, we get:

4x + 6 = 42;

(4x + 6) / 4 = 42/4;

x + 1.5 = 10.5;

x = 10.5 – 1.5 = 9 cm.

Finding the big side:

x + 3 = 9 + 3 = 12 cm.

Answer: 9 cm and 12 cm.