Question

A rectangle is 4 times as long as it is wide. If the length is increased by 4 inches and the width is decreased by 1 inch, the area will be 60 square inches. What were the dimensions of the original rectangle?

Answer 1

The equation can be formatted as (w-1)(l+4) = 60

There are many ways to solve this but I decided to just plug in numbers.

I established w is 7 and L was 6 initially.

The long way to solve this would be by completing the square which is literally impossible to diagram on this website.

Answer 2

Let the Width of the Original Rectangle be : W

Given : Length of the Original Rectangle is 4 times as long as it's Width

⇒ Length of the Original Rectangle = 4 × W = 4W

Now Some Modifications are made, So that Original Rectangle becomes into a New Rectangle.

Given the Length of New Rectangle is 4 inches More than Length of Original Rectangle.

⇒ Length of New Rectangle = 4W + 4

Given the Width of New Rectangle is One Inch less than Width of Original Rectangle.

⇒ Width of New Rectangle = W - 1

We know that Area of a Rectangle is : Length × Width

Given the Area of New Rectangle is 60 inches²

⇒ (4W + 4)(W - 1) = 60

⇒ 4W² - 4W + 4W - 4 = 60

⇒ 4W² - 4 = 60

⇒ 4W² = 64

⇒ W² = 16

⇒ W = 4

Dimensions of Original Rectangle :

Length of Original Rectangle = 4W = 4 × 4 = 16 inches

Width of Original Rectangle = W = 4 inches