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

We know the numbers, they simply don’t match with representing them in other numerical forms. Pi is a classic example, it is the circumference of a circle divided by its diameter. That’s pi. But that ratio doesn’t lend itself to portion of 10 base.