The length of the rectangle is 6 cm. What is its width if the perimeter is 20 cm?

From the condition it is known that the length of the rectangle is 6 cm. In order to find what its width is equal to, if the perimeter of the rectangle is 20 cm, we compose and solve a linear equation.

Let’s use the variable x cm to define the width of the rectangle.

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

P = 2 (a + b);

Substitute all values and calculate:

2 (6 + x) = 20;

Divide both sides of the equation by 2 and get:

6 + x = 10;

We are looking for an unknown term:

x = 10 – 6;

x = 4 cm width of the rectangle.

Answer: 4 cm.