Question 187055
I would try to find out which of those two options ends up with the ratio of the areas of the two figures being closest to 1.

For the circle inside the square, let the square have a side of 1. Then the circle has a diameter of 1. Now find the ratio of the area of the circle to the area of the square. (littler area over the larger area).

Then do the same for the square inside the circle. Let the side of the square be 1. In this case the diameter of the circle is sqrt(2). Now find the ratio of squareArea/circleArea. 

The ratio that is closest to '1' is the set that 'fits better' IMHO