A circle in a square consumes more percentage of the area of the square ie., only 21.46% of the area is wasted.
On the other hand Square in circle wastes more area ie., 36.33%
For the circle in the square case to find the area that is wasted by the circle in the square in percentage we can use the following method
=(1 - (πr^2/s^2)) *100 ------ 1
so 1 becomes
Similarly in the case of the square inside the circle we end up with the equation
(1 - (s^2/πr^2))*100 ------ 2
so 2 becomes
(1 - (2/π))*100
So we can conclude that the circular pizza consumes more percentage area of the square box it is in than the vice versa case.