The length of a rectangle is 3 times its width. Find the area of a rectangle if its width is 12cm less than its length.

The area of the rectangle is calculated using the following formula:

S = a * b.

In this formula, a is length, b is width.

Let’s compose the equations according to the conditions of the problem.

1) a = 3 * b.

2) b = a – 12.

Let us express a from the first equation.

a = b + 12.

Substitute the value of a into the first equation.

b + 12 = 3 * b.

2 * b = 12.

b = 6 cm, the width of the rectangle.

Now we determine the length of this rectangle.

a = 6 + 12 = 18 cm.

Let’s calculate the area of the rectangle.

S = 18 * 6 = 108 cm2.

Answer: the area of this rectangle will be 108 cm2.