How much of PI is known?
At one level a huge deal. Pi is known to an accuracy of the
width of a hydrogen atom at the far end of the known universe.
At the same time, since pi is an irrational number, it has an
infinitely long decimal representation with no recurrence. So even
if we knew 1 quadrillion digits of pi (we don't yet) we would only
know one quadriliion infinitieth (to coin a word) of pi - that is
0%.