# Thread: circumference of a circle

1. ## circumference of a circle

If the circumference of a circle is 4*pi/3, then what is half of its area?

a 2*pi/9
b.4*pi/9
c.8*pi/9
d.2*pi squared/9

2. Originally Posted by Schatzle06
If the circumference of a circle is 4*pi/3, then what is half of its area?

a 2*pi/9
b.4*pi/9
c.8*pi/9
d.2*pi squared/9
$2\pi r=\frac{4\pi}{3}$
Divide by $\pi$ to get,
$2 r=4/3$
Divide by 2,
$r=2/3$.
Thus,
$A=\pi (2/3)^2=(16/9)\pi$
Half of that is,
$(8/9)\pi$