Pi is a constant number, meaning that for all circles of any size, Pi will be the same. According  to The Tau Manifesto, "pi is a confusing and unnatural choice for the circle constant." Far more relevant, according to the algebraic apostates, is 2π, aka tau. So, there has been discrepancies against the reliability of Pi.     It is quite hard to know exactly whom has found pi, however Pi has been aware of since about 2550 B.C. The earliest textual evidence of pi dates back to 1900 BC; by th