Question #N779
A circle with radius $r$ is inscribed in a square. If the area of the square is 64, what is the area of the circle in terms of $\pi$?
A. $4 \pi$
B. $8 \pi$
C. $16 \pi$
D. $64 \pi$
Correct Answer is: C
Since the circle is inscribed in the square, the diameter of the circle is equal to the side length of the square. The area of the square is 64, so the side length of the square is $\sqrt{64} = 8$. The diameter of the circle is 8, so the radius is 4. The area of the circle is $\pi r^2 = \pi (4)^2 = 16 \pi$.