The Pythagorean theorem and pi are both mathematical features that fall out of a particular model of the world, namely Euclidean geometry, which is an inaccurate model for at least two historically major reasons (the Earth not being flat and relativity).
How does “the Earth not being flat” make Euclidean geometry inaccurate?
If you draw a big enough right triangle on the Earth, it will visibly fail to satisfy the Pythagorean theorem. The geometry of the Earth is approximately spherical geometry, not Euclidean geometry.
How does “the Earth not being flat” make Euclidean geometry inaccurate?
If you draw a big enough right triangle on the Earth, it will visibly fail to satisfy the Pythagorean theorem. The geometry of the Earth is approximately spherical geometry, not Euclidean geometry.
Euclidean geometry is a set of principles and conclusions for flat space. That Earth is not flat in no way makes Euclidean geometry inaccurate.