It's written using the Greek letter π, pronounced "pie." National Pi Day is actually a U.S. holiday, declared in 2009. But schools aren't closed, and banks are open.
While Pi isn't edible, making pies has become as much a part of Pi Day as the ratio used to compute the circumference, area, and volume of circles — which is 3.14159 plus.
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Not sure how to celebrate?
- Have a piece of pie: key lime, apple, cherry, chocolate silk, even pizza pie.
- Keep an eye out for restaurant specials: $3.14 as a price, or a free slice of pie after your meal.
- Connect with other math geeks.
- Challenge each other to recite Pi to as many digits as possible.Listen to The Pi Song.
Schoolchildren often are encouraged to have math bees, like spelling bees, in which they recite as many decimals of Pi as possible. Winners, of course, get pie.
Pi Day also is Albert Einstein's birthday. The German theoretical physicist was born on March 14, 1879.
According to the Pi Day website www.piday.org, "Pi has been calculated to over one trillion digits beyond its decimal point."
Attempts to memorize the value of π with increasing precision have led to records of over 67,000 digits, according to Wikipedia.
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