1. area, perimeter and units

if we have a circle with perimeter 30 cm, how many cm^2(exactly) are in the circle area? in other words, how many square units(cm^2)(but exactly) are there, if i were count them?
Thanks for your supports and sorry for my languages...

2. $
2\pi r = 30 \Leftrightarrow r = \frac{{30}}
{{2\pi }} \Rightarrow A_ \odot = \pi \left( {\frac{{30}}
{{2\pi }}} \right)^2
$

3. Originally Posted by Nacho
$
2\pi r = 30 \Leftrightarrow r = \frac{{30}}
{{2\pi }} \Rightarrow A_ \odot = \pi \left( {\frac{{30}}
{{2\pi }}} \right)^2
$
thanks but u calculate circle area. i want to count only exact square units(not semi-square or another) in the circle area...i hope i can explain the problem correctly....

4. Originally Posted by turkmath
thanks but u calculate circle area. i want to count only exact square units(not semi-square or another) in the circle area...i hope i can explain the problem correctly....
Do you mean how many actual squares, 1 cm on a side, can be put into the circle without overlapping?

5. Originally Posted by HallsofIvy
Do you mean how many actual squares, 1 cm on a side, can be put into the circle without overlapping?
totally yes, yes...this is true question and good meaning...

6. is it complicate or advanced question?

7. pls help, thanks for your supports...

8. it is still unsolved... Can i use any math software for solving this problem?Thanks for your comments...