The perimeter of the rectangle is 20dm. The length of its smaller side is 4dm. What is the length of the larger side?

It is known from the condition that the perimeter of the rectangle is 20 dm, and the length of its smaller side is 4 dm. In order to find what is the length of the longer side, we compose and solve a linear equation with one variable.

Let’s use the variable x to denote the larger side of the rectangle.

Let’s remember the formula for finding the perimeter of a rectangle.

P = 2 (a + b);

Substitute the known values into the formula and solve the resulting equation:

2 (4 + x) = 20;

4 + x = 20: 2;

4 + x = 10;

x = 10 – 4;

x = 6 in. large side of the rectangle.

Answer: 6 dm.