Interesting: Approaching to pi

It's interesting that answer approaches to pi number without decimal point. If you'll increase r, answer becomes more and more precisely. For example: answer for r = 1e5 is 31416325412, but for r = 1e9 (although r < 1e5) is 3141592657589764752, when pi equals to 3.141592653

Anybody knows why it's happens?

*Edited by author 28.12.2017 02:31*

*Edited by author 28.12.2017 02:31*