How can we use irrational numbers in math if we don’t know the full number?

Question

How can we use irrational numbers in math if we don’t know the full number?

In: 232

Answer 1

To calculate the circumference of the universe down to the accuracy of the diameter of a hydrogen atom?

37 decimal places of pi is MORE than enough

https://www.jpl.nasa.gov/edu/news/2016/3/16/how-many-decimals-of-pi-do-we-really-need/

So while we don’t know the EXACT number, we know that we don’t need it to be exact for any practical work

This applies to all irrational numbers, there becomes a point where it doesn’t really matter. We’re within the width of a hydrogen atom, why do we need more?