The formula of the area of a circle is :

You know that the area is 1256.
So :

Divide both sides by

:

<span> take the square root of both sides in order to obtain r :
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In short, the answer would be 20 (i have rounded).
Hope this helps !
Photon
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Answer:
False
Step-by-step explanation:
9 cannot be equal to 31
It is 16,700 meters to cycle there and back
Answer:
x^2 / 4pi
Step-by-step explanation:
The area of a circle is (pi x r)^2
The circumference of a circle is 2pi x r
The find the radius, you need to divide x by 2pi, so x / 2pi
Then just plug it in as the radius:
(pi x (x / 2pi))^2 = x^2 / 4pi