Question

The length of a rectangle is 4 feet shorter than its width. the area of the rectangle is 42 square feet. find the length and width. round your answer to the nearest tenth of a foot

Answer 1

Let the length of the rectangle to be a value, x.

Since you are told that the length is 4 feet shorter than width, then, this can only mean that 
width = (x+4)
The area of a rectangle = length × width. 
                                      = x(x+4) = 42
                                      =x² + 4x=42
 From here form the quadratic equation then solve it to get the value of x (length of the rectangle)

x²+4x-42=0
Using the quadratic formula,


x = -4 + or - (√(16-4×1×-42))÷2

At this point I had a problem with inserting an equation in this platform. So, i have done it have attached a file that explains the above statement. Kindly find it in the attachment below.  

x = (-4+or - 13.56)÷2
  = 9.56÷2
  =4.78 feet
The length to the nearest foot = 5 feet.
The width to the nearest foot = 5+4 = 9 feet.

Download pdf