The length of a rectangle is three times its width. Find the area of a rectangle if its width is 12 cm less than its length.

Let the value of the width of the rectangle be x, then since the length of the rectangle is three times its width, then the value of the length of the rectangle is 3x. Since the width of the rectangle is 12 cm less than the length, we can write that the length of the rectangle is 12 + x cm.We get the equation: 3x = 12 + x, 3x – x = 12, 2x = 12, x = 12: 2, x = 6 cm. The value of the width of the rectangle is 6 cm, and the value of the length is 6 * 3 = 18 cm. The area of the rectangle is equal to the product of length and width. The area of the rectangle is: S = 6 cm * 18 cm = 108 cm square.