More likely a mathematician would correct you instead of crying. Pi is not infinite, its decimal expansion is infinite!
Easy. Take a wire that is exactly 1 meter long. Form a circle from the wire. The circumference of that circle is 1 meter.
Who said Pi is infinite? If we take Pi as base unit, it is exactly 1. No fraction, perfectly round.
Now everything else requires an infinite precision.
I'm confused, how is pi used as a unit? My understanding is that it's a number
1 is also a number, a number we chose by convention to be a base unit for all numbers. You can break down every number down to this unit.
20 is 20 1s. 1.5 is 1 and a half 1.
If we have Pi as a unit, circumference of a circle would be radius*2 of Pi units. But everything that doesn't involve Pi would be a fraction of Pi, e.g. a normal 1 is roughly 1/3 of Pi units, 314 is roughly 100 Pi units, etc. etc.
