The number pi (symbol: π) is a mathematical constant that is the ratio of a circle's circumference to its diameter. It has been represented by the Greek letter "π" since the early 1700s. Its decimal representation never settles into a permanent repeating pattern and never ends. The ubiquitous nature of π makes it one of the most widely known mathematical constants, both inside and outside the scientific community. This book denotes π to 100,000 decimals.