Pi, also known by the Greek letter “π,” is a constant value used in math that represents the ratio of a circumference of a circle to its diameter, which is 3.14….15…9265359… (and so on, and so on). The fourteenth of March is also Albert Einstein’s birthday, so it’s a mathematician’s delight.
The value of pi was first calculated by Archimedes of Syracuse (287–212 BC), one of the greatest mathematicians of the ancient world.
In the 1630s William Oughtred, an English Clergyman and highly respected mathematician, began to experiment with new mathematical symbols like x for multiplication and :: for proportions. He introduced ‘greater than and less than’ symbols, now the familiar < and >, and he used the Greek letter π for the circumference. The symbol was later embraced by the scientific community when Leonhard Euler used the symbol in 1737.
In 1988, physicist Larry Shaw linked the March 14 date with the first digits of pi (3.14) in order to organize a special bonding day for the San Francisco Exploratorium staff. He offered fruit pies and tea to everyone starting at 1:59 pm, the following three digits of the value.
After his daughter remarked that the special date was also the birthday of Albert Einstein, a celebration of the life of the world-famous scientist was incorporated. Pi Day became an annual Exploratorium tradition. It didn’t take long for the idea to grow exponentially, hitting a peak on March 12, 2009, when the U.S Congress declared it a national holiday.
On Pi Day 2015 the first ten digits of pi lined up for a once-in-a century occurrence, at 9:26:53 a.m. (3/14/15/92653). In 2019 Emma Haruka Iwao, a Google employee from Japan, calculated Pi to a new world record length of 31 trillion digits with the help of the company’s cloud computing service.
Pi Day is celebrated all around the circumference of the world and not just by Math geeks. Pi Day has become a pop culture phenomenon, with 55% of Americans saying they will Celebrate Pi Day. Many bakeries and Pizza restaurants have Pi Day specials.