How to find the radius of a circle if its area is 314 square miles?

The formula for the area is A = pi x r^2 (I don't know how to type out mathematic notation!)

So you have to shift the equation around algebraically to find "r"(radius).

First divide both sides by pi; this eliminates pi from the right hand side of the equation and changes the left to A/pi. Now we have:

A/pi [area divided by pi]=r^2 [radius squared]

In order to isolate "r", we need to take the square root of both sides.

So now,

square root of (a/pi) = r

Because you know the area, you can plug it into this equation to solve for r, radius.  Remember the order of operations: divide area by pi FIRST, then take the square root of that number.

If you don't understand one of the steps, I hope you'll let us know.  You need to learn how to do this!  : )