How Wide is the Garden?

Date: 01/06/98 at 20:46:21
From: Megan Breen
Subject: Pre Algebra-word problems

Shawn puts a fence around the perimeter of a rectangular garden. 
He uses 136 feet of fencing. The garden is 40 feet long. How wide is 
it? 

Date: 01/08/98 at 11:24:54
From: Doctor Jennifer
Subject: Re: Pre Algebra-word problems

Hello Megan!

First you have to see what kind of information was given to you. You 
were given the amount of fencing that was used (perimeter), the length 
of one side, and the fact that it was a rectangular garden.

Now examine what each piece means. The length of fencing is the 
perimeter. What is the perimeter? The perimeter is the sum of the 
sides of the rectangle. Next think about what a rectangle is.  A 
rectangle is a four-sided figure with 2 sets of equal sides and 
4 right angles.  Finally, you know the length of one side.

You can set up an equation:

   x+x+y+y = p
   x - one side of the rectangle
   y - other side of rectangle
   p - perimeter

Then you have the equation x+x+40+40 = 136.  Then you can simplify: 
 
         2x+80 = 136

Finally, you solve for x:

      2x+80-80 = 136-80

Subtract 80 from both sides in order to get the x term alone:

            2x = 56

Then divide both sides by 2 do get the x alone:

          2x/2 = 56/2
             x = 28

Looking  back at the chart, you now know that x is the length of the 
missing side and that the garden is a 40 x 28 rectangle.

Hope this information is helpful. If you have any more questions just 
ask.

-Doctor Jennifer,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/