March 14, 2015:Â Pi, or Ï€, is the ratio of the circumference of a circle to its diameter. Itâ€™s usually shortened to 3.14, which is why March 14 is celebrated every year as Pi Day, but itâ€™s an irrational number that continues infinitely without a pattern, like so: 3.14159265358979323846264338327950288419716939937510582â€¦
The year 2015 marks a very special Pi Day, one that comes only once a century: 3.14.15. Hence some once-in-a-lifetime Pi Day celebrations and promotions around the country are planned for this Saturday.
But whatâ€™s the big deal about pi in the first place?
â€œTo mathematicians, pi is a powerful superhero that turns up all the time in a huge range of mathematical problems,â€ Keith Devlin, Stanford University mathematician and the NPR â€œMath Guyâ€, explained recently to USA Today. â€œPi deserves its special day.â€
Unsurprisingly, the are many Pi Day promotions thatâ€™ll get math nerds excited: For instance, the American Mathematical Society is discounting its publications (40% off for members, 25% off for nonmembers) for orders placed using the code MT159 from March 14 through the end of the month. Itâ€™s just like Black Friday!
There are plenty of deals meant to appeal to C students who hated math too. The fast-casual Blaze Pizza chain is offering any pizza for $3.14 on Pi Day. Your Pie, a pizza restaurant franchise in the southeastern U.S., is knocking $3.14 off pizzas and handing out free gelato and pi-related swag on Saturday. Up in New England,Portland Pie Company locations host an annual customer appreciation day on Pi Day, and on 3.14.15 they will be selling $3.14 pints of beer, $3.14 kids meals, and $3.14 10-inch specialty pizza pies.