Let area of Circle B = Pi * r^2
Therefore, area of Circle A = 3Pi * r^2 ; and area of Square = 6Pi * r^2

In an inscribed circle, the diameter of the circle = Side of the square.

To calculate the area of the inscribed circle, therefore, we first need to determine what the side of the square is.

Since area = Side ^2:

SIDE ^2 = 6Pi * r^2
SIDE = Sqrt ( 6Pi) * r

But this SIDE = Diameter of inscribed circle. Divide by 2, to get Radius of inscribed circle.

Proceed from there to calculate the ares of Inscribed circle in terms of "r", and then calculate the ratio to get the answer.

Please let me know if you have any further questions.