March 14 is a great day for fans of math. And pies or pizza.
Thursday marks Pi Day, held on March 14 in honor of 3.14, the measurement calculating the ratio of a circle’s circumference to its diameter.
But it’s more than just math. Taking advantage of the pronunciation, people celebrate by breaking out pies of varying kinds (apple, cherry, and even pizza), while businesses roll out their best Pi Day deals.
Here’s everything you need to know about Pi in all its forms.
What’s the history of Pi?
According to the Exploratorium, a museum based in San Francisco, Pi (π) was first used nearly 4,000 years ago by the ancient Babylonians, calculating the area of a circle by taking three times the square of its radius.
The number has been calculated multiple times since by renowned mathematicians including Archimedes and Zu Chongzhi. The Pi symbol was introduced in 1706 by mathematician William Jones, but made popular more than 30 years later by Swiss mathematician Leonhard Euler.
How did Pi Day get started?
Former physicist Larry Shaw, who connected March 14 with 3.14, celebrated the first Pi Day at the Exploratorium with fruit pies and tea. The museum said Shaw led Pi Day parades there every year until his passing in 2017. In 2009, the House of Representatives passed a resolution marking March 14 as National Pi Day.
March 14 is big in science circles, too
It’s not just Pi Day. March 14 is also the birthday of famed physicist Albert Einstein. March 14, 2019, also marks the one-year anniversary of the death of Stephen Hawking.
What’s the deal with pie and pizza?
Several pizza chains are offering a variety of pizzas priced at $3.14 honoring Pi Day. It’s also a great time to buy pie. For example, fast food chain Bojangles is selling three sweet potato pies for $3.14. This is the kind of math we can get behind.