The perimeter of the rectangle is 18cm. Its length is 3 cm greater than its width. Find the lengths of the sides of the rectangle.

1) Knowing that the length is 3 cm more than the width and that the rectangle has two such lengths, we find out how many cm are two lengths more than two widths: 3 2 = 6 (cm);

2) Subtract the difference of 6 cm from the perimeter of the rectangle and get the perimeter of a square with four equal sides, which are equal in size to the width of this figure: 18 – 6 = 12 (cm);

3) Determine the width: 12: 4 = 3 (cm);

4) Find out what the length is equal to: 3 + 3 = 6 (cm).

5) Check: P = 3 + 3 + 6 + 6 = 18 (cm).

Answer: width – 3 cm, length – 6 cm.