How was pi invented?

Answer 1

It was discovered by the fact that the circumference of any circle when divided by its diameter is equal to pi.

The earliest evidenced conscious use of an accurate approximation for the length of a circumference with respect to its radius is of 3 + 1/7 in the designs of the Old Kingdom pyramids in Egypt. The Great Pyramid at Giza, constructed c.2550-2500 BC, was built with a perimeter of 1760 cubits and a height of 280 cubits; the ratio 1760/280 ≈ 2π

(Courtesy of Wikipedia, Pi)

Answer 2

Mathematicians began using the Greek letter π in the 1700s. Introduced by William Jones in 1706, use of the symbol was popularized by Leonhard Euler , who adopted it in 1737. An eighteenth-century French mathematician named Georges Buffon devised a way to calculate π based on probability.