The perimeter of the rectangle is 48 cm and its width is 6 cm. Find the length of this rectangle.

The perimeter of a rectangle is the sum of the lengths of all its sides. Since in a rectangle the opposite sides are equal, then P = 2 * (a + b), where a is the length, b is the width. We calculate what the length of the rectangle is, knowing that the perimeter is 48 centimeters and the width is 6 centimeters.
(a + 6) * 2 = 48;
a + 6 = 48/2;
a + 6 = 24;
a = 24 – 6;
a = 18;
Answer: 18 centimeters.