sandy wrote:
A circle has a circumference of 16. What is its area?
(A) \(\frac{8}{\pi}\)
(B) \(\frac{8}{\pi^2}\)
(C) \(\frac{64}{\pi}\)
(D) \(\frac{64}{\pi^2}\)
(E) \(64\pi\)
Circumference of a circle \(= 2\pi r\) We can write: \(2\pi r = 16\)
Divide both sides of the equation by \(2 \pi\) to get: \(r = \frac{16}{2\pi}=\frac{8}{\pi}\)
Now that we know the circle has a radius of \(\frac{8}{\pi}\), we can calculate the area...
Area of a circle \(= \pi r^2\) Area \(= \pi (\frac{8}{\pi})^2\)
\(= \pi (\frac{64}{\pi ^2})\)
\(= \frac{64 \pi}{\pi ^2}\)
\(= \frac{64 }{\pi}\)
Answer: C
Cheers,
Brent