Pi (π) is a mathematical constant representing the ratio of a circle's circumference to its diameter, approximately 3.14159, and the Greek letter 'π' was adopted as its symbol because it's the first letter of the Greek words for "perimeter" or "periphery," chosen by William Jones in 1706 and popularized by Leonhard Euler. The number itself has always existed as this fixed ratio, fundamental to geometry, but the symbol became standard shorthand for it centuries ago. #Pi(π) #mathematics #verygood