Pi Day is celebrated annually on March 14 (Credit: www.visitprinceton.org)

Celebrated annually on March 14, Pi ("π”) Day is a universal favorite with students and teachers. Though the American holiday, which honors the numerical constant representing the ratio of a circle's circumference to its diameter, typically begins with a classroom discussion of the symbol, it usually ends with a slice or two of delicious pie. The event is commemorated every March 14 because the irrational number, which continues infinitely without repetition or pattern, is widely recognized as 3.14.

The fun tradition, which coincides with Albert Einstein's birthday, began on March 14, 1988, when Larry Shaw, a physicist at San Francisco's Exploratorium, asked colleagues to mark the day by walking around one of the museum's circular spaces and eating fruit pies. As word of the fun celebration grew, schools countrywide began adopting the custom, and in 2009, US lawmakers declared Pi Day an official holiday.

Many pizza chains offer discounts on Pi Day ( Credit: Ludie Cochrane/CC-BY-SA 2.0/Flickr)

Pi Day is now also celebrated by restaurants with special deals on both sweet and savory pies. In 2020, Blaze Pizza will continue its six-year-old tradition by offering its 11-inch pizza for just $3.14 each. "Math gives us a blueprint to solve a problem, whether simple or complex. It's with that same spirit that Blaze Pizza was founded -- to solve the important problem of how to get an insanely great, scratch-made pizza that's both fast and affordable," said Jim Mizes, former president and CEO. "This year, we calculated that we will serve more than a quarter-million pizzas at $3.14. We look forward to having Blaze fans across the US and Canada come in to celebrate with us."

Those who do not have a Blaze Pizza nearby can visit the neighborhood 7-Eleven store, which plans to sell whole pizzas for $3.14 and slices for a mere $0.50 on March 14, 2020. Though Papa Murphy's offer is not as generous, the pizza chain will discount all orders of over $20 by 31.4 percent. Looking for something sweeter? Then head over to Marie Callendar's for a free slice of pie with the purchase of an adult entree.

#DressforStem movement was started by female meteorologists to encourage more girls to pursue STEM careers (Credit: #DressforStem/Twitter)

Since 2015, to help raise awareness and to encourage more girls to pursue careers in science, technology, engineering, and mathematics (STEM), female television meteorologists have been wearing purple on Pi Day. This year, they are asking females of all ages and backgrounds to join the burgeoning #DressforSTEM movement by donning purple on March 13 and March 14.

NASA's Jet Propulsion Laboratory will join in the fun with its annual "Pi In the Sky" challenge. The fun activities are designed to encourage students from 5th to 12th grade to help NASA scientists and engineers solve real-world problems using pi. This year's challenges include using Pi to calculate the perfect spot to land on Mars and to measure the time it takes for Arrokoth — the most distant and primitive object in the solar System ever explored by a spacecraft — to revolve around the Sun.

NASA's "Pi in the Sky" challenge offers fun Pi Day activities for kids (Credit: www.jpl.nasa.gov)

Pi Day is particularly anticipated by high school students hoping to attend the Massachusetts Institute of Technology (MIT), since that's when the elite school e-mails its decision letters. However, instead of sending out notifications at 3:14 pm EST, as would be expected, the officials do it at 6:28 pm EST. Referred to as tau, the number — which is pi multiplied by 2 — is believed to be much more reliable than pi by some mathematicians and even has its own celebration on June 28 (6/28). Since 2017, MIT has also used Pi Day as a fundraiser to support its students, faculty, and programs.

Though Pi Day celebrations are relatively new, pi has been around for thousands of years. The Babylonians first used it about 4,000 years ago to calculate the area of a circle by taking three times the square of its radius, giving pi a value of 3. The ancient Egyptians came closer to the real number with 3.165 in 1650 BC. Archimedes of Syracuse (287-212 BC) was the first to calculate pi mathematically. However, the Greek scholar was well aware that his number, which varied between 3 1/7 and 3 10/71, was just an approximation. Given that all the numbers were derived without computers, their proximity to pi's actual value is truly impressive!

Happy Pi(e) Day!

Resources: Jpl.nasa.gov, www.deseret.com, wikipedia.org, www.exploratorium.edu