The area of the rectangle is 64 dm2. the length is 4 times the width. What is the perimeter of the rectangle?

Suppose the width of the rectangle is a dm.
Since it is known that its length is 4 times its width, it means that it will be:
4 * a dm.
We get the equation:
a * a * a = 64.
4 * a ^ 2 = 64.
a ^ 2 = 64/4 = 16.
a = √16 = 4 dm (width).
4 * a = 4 * 4 = 16 dm (length).
To find the perimeter of a shape, multiply the sum of the length and width by 2.
Will be:
2 * (4 + 16) = 2 * 20 = 40 dm.
Answer: The perimeter of the rectangle is 40 decimeters.