how do you find the exact area of a circle

Question

anonymous · Answer

by using the exact equation:
$$A=\pi r^2$$

anonymous · Answer

if you can use the eact number for PI (which does not exist, since it it irrational!!), you'd gert an exact answer.
Hence, one can never have an exact area !!!

anonymous · Answer

yeah but my teacher said some thing about how you can represent the exact area with symbols

anonymous · Answer

what symbols? could you elaborate?

uri · Answer

By using integration? :P

anonymous · Answer

@uri no. this seems like high-school question.

anonymous · Answer

like, you use the pie symbol in front of a number which I think may be radius^2 but I am not sure

uri · Answer

Oh my bad. He said symbols; so I assumed integration. lol.

anonymous · Answer

lol

anonymous · Answer

@uri, you also assumed its a "he"!! but

uri · Answer

lol sorry..my assumptions tend to fail. :P

anonymous · Answer

@VIVVI163, like I explained before,
the area of a circle is 
$$A=\pi r^2$$
where $\pi$ is an irrational number.
so, if you are given a circle of radius "r=3cm", then the area of that circle would be 
$A=\pi\times5^2=\mathbf{25\pi {\rm cm^2}}$

anonymous · Answer

ooo thanks I guess I just needed to hear it explained differenly thanks

anonymous · Answer

now, if you try to put in the "value" for $\pi$ and multiply it out, then you'd have rounding errors and will never have an exact answer.
so, I assume you are looking for an answer where you do $r^2$ an leave the answer as 
that value times pi

anonymous · Answer

sure. you are welcome.

anonymous · Answer

yea that's just what O needed