I wanted to know how to calculate the perimeter of a rectangle if its area is 10.

I know that A=l x w

and Perimeter = 2l + 2W

How would i go about calculating the perimeter if its a Rectangle ?

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- Jun 8th 2012, 04:57 AMMikeNoobCalculating perimeter with only area of a rectangle
I wanted to know how to calculate the perimeter of a rectangle if its area is 10.

I know that A=l x w

and Perimeter = 2l + 2W

How would i go about calculating the perimeter if its a Rectangle ? - Jun 8th 2012, 05:00 AMProve ItRe: Calculating perimeter with only area of a rectangle
There are an infinite number of possibilities. Let $\displaystyle \displaystyle \begin{align*} lw = 10 \implies w = \frac{10}{l} \end{align*}$.

Then from the second equation we have

$\displaystyle \displaystyle \begin{align*} P &= 2l + 2w \\ &= 2l + 2\left(\frac{10}{l}\right) \\ &= 2l + \frac{20}{l} \end{align*}$

Obviously the perimeter will change if you change the value of w. - Jun 8th 2012, 05:05 AMPlatoRe: Calculating perimeter with only area of a rectangle
- Jun 8th 2012, 05:07 AMMikeNoobRe: Calculating perimeter with only area of a rectangle
I dont want to create another thread for this question what if a question states to find the length and width of a rectangle if its area is 48 and perimter is 28. The way i am doing it is that i am ending up with a quadratic equation. Any suggestion.

- Jun 8th 2012, 05:13 AMProve ItRe: Calculating perimeter with only area of a rectangle
- Jun 8th 2012, 05:19 AMMikeNoobRe: Calculating perimeter with only area of a rectangle
I end up with the following equation:

l(square) + 48 -14l =0

When applying the quadratic formula i dont get the answer plus i get two values .. there must be an easier and a quicker way of solving this, - Jun 8th 2012, 05:23 AMPlatoRe: Calculating perimeter with only area of a rectangle
- Jun 8th 2012, 05:51 AMProve ItRe: Calculating perimeter with only area of a rectangle
- Jun 8th 2012, 07:02 AMMikeNoobRe: Calculating perimeter with only area of a rectangle
I get 8 and 6 ? how should i know which one to use ??

- Jun 8th 2012, 07:12 AMPlatoRe: Calculating perimeter with only area of a rectangle