The formula of the area of a circle is : [tex]A= \pi R^2[/tex]
You know that the area is 1256.
So : [tex]1256= \pi R^2[/tex]
Divide both sides by [tex] \pi [/tex] :
[tex] \frac{1256}{\pi}=R^2[/tex]
take the square root of both sides in order to obtain r :
[tex]\sqrt{ \frac{1256}{ \pi }}=R[/tex]
[tex]20=R[/tex]
In short, the answer would be 20 (i have rounded).
Hope this helps !
Photon
