Bunuel wrote:

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

(1) The area of the square is 18.

(2) The circumference of the circle is \(6\pi\).

We are given that square is inscribed in a circle, but we dont know whether its the largest possible square inscribed in that circle or not.

To solve this question, we need to know the radius of this circle.

(1) Area of square = side*side = 18. So side of square can be found but we dont know whether its the largest possible square which can be inscribed in this circle, so we cannot apply the relation that diagonal of this square = diameter of this circle. So we cannot find the diameter or the radius of this circle. So not sufficient.

(2) Circumference is given, so we can find the radius, and can thus find the area. Sufficient.

Hence

B answer