The length of the rectangle is 13 cm longer than its width. The area of the rectangle is 140 cm. Find the perimeter of the rectangle.

To solve, we introduce the variable x.

Let’s assume that the width of the rectangle is x.

Since, by condition, the length of the rectangle is 13 cm greater than its width, the length is x + 13.

The problem says that the area of the rectangle is 140, then: x * (x + 13) = 140, where x = 7 is the width, then the length is 7 + 13 = 20 cm.

Along this, the perimeter is: 20 + 20 + 7 + 7 = 54 cm.