The atom's size would be the same no matter the circumference since the circle and the formula are infinite...
I am not sure what you mean here! A circle, whether the radius is 2 inches or 150 million light years, is not infinite in any way that I understand the meaning of that word.
This is what I am saying: A 2 inch circle has a (finite) circumference. It can be approximated to by C =
π x D. If you take a value of
π with no decimal places (3) then the circumference comes out as 6 inches. Let us take values of
π with increasing numbers of decimal places:
The circumference becomes (inches):
6
6.2
6.28
6.282
6.283
6.28318
6.283184
6.2831852
6.2831853
6.283185302
We are getting nearer all the time to the actual circumference (the error is getting less and less). Now if we used pi to 39 decimal places the difference between the actual diameter and the calculated figure would be very small. If the circle was 20 billion light years across, the error would be around the size of a proton (2 x 10 to the power of -15) metres. It follows that the error for a 2 inch circle would be less, in the same proportion as the ratio of 2 inches to 20 billion light years.
