SOLUTION: area of a rectangle= 220 square feet. find the diminensions of the figure. ----------- -------- x-9 |

SOLUTION: area of a rectangle= 220 square feet. find the diminensions of the figure. ----------- -------- x-9 | | |

Question 178500: area of a rectangle= 220 square feet. find the diminensions of the figure.

--------------------
x-9 | |
| |
| |
--------------------
x
Found 2 solutions by nerdybill, jim_thompson5910:
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
Since we know that area of any rectangle is:
"width" * "length"
.
We then have:
x(x-9) = 220
x^2 - 9x = 220
x^2 - 9x - 220 =0
(x-20)(x+11) = 0
.
x = {20, -11}
.
We can toss out the negative solution leaving us with:
x = 20 feet
x-9 = 11 feet
.
Therefore, the dimensions are:
20 feet by 11 feet
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
Let Length=x and Width=x-9 Note: the order does not matter, but the length is usually the longer of the two.

Start with the area of a rectangle formula

Plug in , and

Distribute

Subtract 220 from both sides.

Notice we have a quadratic equation in the form of where , , and

Let's use the quadratic formula to solve for x

Start with the quadratic formula

Plug in , , and

Negate to get .

Square to get .

Multiply to get

Rewrite as

Add to to get

Multiply and to get .

Take the square root of to get .

or Break up the expression.

or Combine like terms.

or Simplify.

So the possible answers are or

However, since you can't have a negative length, this means that only solution is

So the length is and the width is

==============================================

Answer:

So the length is 20 ft and the width is 11 ft
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