March 14 is Pi Day, an annual celebration of the mathematical constant pi (π), the ratio of the circumference of a circle to its diameter.
The symbol was first used in mathematical calculations by Welsh mathematician William Jones and later it was popularized by Swiss mathematician Leonhard Euler, who adopted it in 1737.
However, the numerical relationship between a circle’s diameter and circumference has been considered since antiquity.
The Babylonians (c. 2000 BC) used 3.125 to approximate pi, while the Egyptians 3.160. In the Bible the bowl in King Solomon’s Temple used for ablution of the priests had a diameter of 10 cubits and a circumference of 30 cubits which places the ratio at 3.
Its value is often rendered as 3.14 but that is an approximation. The real value of pi is 3.1415926535 followed by a string of digits that goes indefinitely, because it is an irrational number. In its endless stream of digits, pi is believed to contain the numbers 0 through 9 in every imaginable combination, also our phone number, social security number, ATM…
Pi Day is held on March 14 because in the American date format it is 3/14. In addition, it is Albert Einstein’s birthday… and physicist Stephen Hawking — considered by some to be Einstein’s intellectual successor — died on March 14, 2018.
Pi Day started in 1988 at the San Francisco Exploratorium, where the first official celebration was organized by physicist Larry Shaw.
Pi Day may be observed by eating pie, to celebrate the pun as the two words are homophones (they sound the same) and many pies have a circular shape.
Image: Wikimedia Commons, – Matman from Lublin -Apple pie Pi Day