A history of pi and its birthday

By Advay Koranne ‘20

This last Saturday, March 14, 2020, was Pi Day. The name “Pi Day” comes from the fact that the first three digits of pi (3.14) happen to align with the date 3/14/20. This date also coincidentally aligns with the birthday of famous theoretical physicist Albert Einstein and the death of Stephen Hawking. Pi –– the ratio of the circumference of a circle to its diameter –– is one of the most commonly known mathematical constants. This constant can be found in everything around us, ranging from the way rivers bend to allowing us to send things to the moon.

Pi Day, Pie. Photo courtesy of Wikimedia Commons.

A Brief History of Pi:

The value of pi has been known for almost 4000 years. However, since Pi is a transcendental number –– a number that will repeat forever –– every century, there has been large progress made in calculating the digits of pi with more accuracy.

Record approximation of pi. Photo courtesy of Wikimedia.

The Babylonians were one of the first to find the value of pi. They found this by taking three times the square of a circle’s radius. Famous mathematician Archimedes approximated the value of pi to a closer value by drawing closed polygons inside of the circle and found that the value of pi has to be in between the values (3 and 1/7) and (3 and 10/71). Another mathematician Zhu Chongzhi who did know Archimedes' method, used the same approach to calculate pi. However, he used a polygon with more sides that, in turn, resulted in a closer approximation of pi. Mathematician Madhavan of Sangamagrama made the next significant milestone in the discovery of even more digits of pi. He discovered a series that we now call the Madhava-Leibniz series, which estimated pi. However, the invention of the computer drastically changed how many digits of pi we could compute. On March, 14, 2019, Google broke the Guinness World Record for pi by computing over 31.4 trillion digits of pi.

History of Pi Day:

Pi Day was started by Larry Shaw, class of ‘61 of Reed College, a physicist who was the technical curator for the Exploratorium in San Francisco. Some also refer to him as the Prince of Pi as he helped organize the first celebration of Pi Day that took place in San Francisco in 1988 in the San Francisco Exploratorium science museum. As Pi Day grew more popular, in 2009, the U.S House of Representatives declared March 14 as National Pi Day.

Let’s start a new tradition in 2021 to celebrate Pi Day on Catlin Gabel’s campus!