A square is inscribed in a circle with radius 5. What is the area of the square?

✓ Correct Answer: Option C

When a square is inscribed in a circle, the diagonal of the square equals the circle's diameter. Diameter = 2 * radius = 2 * 5 = 10. Let 's' be the side of the square. By Pythagoras, s^2 + s^2 = 10^2 => 2s^2 = 100 => s^2 = 50. The area of the square is s^2, which is 50.