Question 497609
<font face="Times New Roman" size="+2">


The area of a circle is given by:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ A\ =\ \pi{r^2} ]


The radius of a circle given the circumference is:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ r\ =\ \frac{C}{2\pi} ]


Combining these facts:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ A\ =\ \pi{\left(\frac{C}{2\pi}\right)^2} ] 


Which simplifies to:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ A\ =\ \frac{C^2}{4\pi} ]


Plug in your value for the circumference (the "distance around") and do the arithmetic to get the area in square miles.  Multiply the area in square miles by 640 acres per square mile.  Round to the nearest 10th because your given measurement was to the nearest tenth.


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ A\ \text{mi^2}\ \times\ 640\ \text{\frac{acres}{mi^2}\ =\ 640A\ \text{acres}]


John
*[tex \LARGE e^{i\pi} + 1 = 0]
My calculator said it, I believe it, that settles it
<div style="text-align:center"><a href="http://outcampaign.org/" target="_blank"><img src="http://cdn.cloudfiles.mosso.com/c116811/scarlet_A.png" border="0" alt="The Out Campaign: Scarlet Letter of Atheism" width="143" height="122" /></a></div>
</font>