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

✓ Correct Answer: Option B

When a square is inscribed in a circle, the diagonal of the square is equal to the diameter of the circle, which is 2R. If 's' is the side length of the square, then s^2 + s^2 = (2R)^2 (Pythagorean theorem), so 2s^2 = 4R^2. This means s^2 = 2R^2. The area of the square is s^2, which is 2R^2.