The number pi is perhaps the most famous irrational number in the world. Most children learn about it in school, and it is popular enough to have its own day. In mathematical formulas, it is written as π, which is the Greek letter "pi." Despite this connection to Ancient Greece, people were aware of the concept of pi in earlier civilizations. Pi has also found a place in popular culture and the hearts of many, but what is Pi really and how was it discovered?


1. What is Pi?

Pi is the ratio of a circle's circumference to its diameter. This is true for every circle, no matter the size. Pi is a mathematical constant and an irrational number, meaning it can't be expressed as a simple fraction. This means that the number is an infinite decimal and mathematicians have proved that the number has no repeating patterns. When working with the number the first five decimal places are generally used, which are 3.14159. Some people also shorten it further to 3.14.

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