Some traditions say, based on a Gemmorah in Taanis 9a (also מדרש רבה נשא י' ו', זוהר פנחס רכ"א א, and more):
"ליכא מידי דלא רמיזא באורייתא"
"There is nothing that is not alluded to in the Torah"
That is, everything can be derived from the written Torah (the Pentateuch of 304,805 letters, and Gr"a adds from Parashat Bereshis alone etc). Many tried (and succeeded) to find certain integers, such as numbers and dates.
In what way can the irrational and infinite number Pi be derived from the written Torah?
(to clarify, the question is not about approximation of Pi, it is about the possibility to derive an irrational number from a list of letters)