Question #N361
A square with side length 10 is inscribed in a circle. What is the area of the circle?
A. 25\pi
B. 50\pi
C. 100\pi
D. 200\pi
Correct Answer is: C
The diagonal of the square is also the diameter of the circle. Since the sides of the square are 10, the diagonal is 10√2 by the Pythagorean theorem. The radius of the circle is half the diameter, so the radius is 5√2, and the area of the circle is π(5√2)² = 50π = 100π.