We usually think of pi as about 3.14 – but there’s more to it than that. “Pi is a fabulous ratio that’s constant across every single circle,” Lesseig said.

National Pi Day is held each year on March 14. It honors 3.14 the ratio of the circumference of a circle. You can also get deals on food too.

Tuesday is Pi Day, a national celebration of the mathematical concept, which is the ratio of a circle's circumference to its diameter and equals 3.14... Schools and museums often plan events to ...

Pi is the ratio of a circle's circumference to its diameter, and, unlike those rows of multiplication tables you were forced to memorize in third grade, it's got true staying power.

What is Pi Day, and why do we celebrate it every March 14? Here's what to know as math lovers around the world mark Pi Day.

Pi is the ratio of a circle's circumference to its diameter. Jana Frank, a franchise owner of Mathnasium, shared some ways to celebrate Pi Day.

It's known that a circle is slightly more than three times its width, around 3.14, and because Pi is represented as a constant, it will be the same no matter what the circle is.

What is Pi? Pi is the ratio of a circle’s circumference to its diameter. It's represented by the Greek letter π. And you thought you'd never use Pi after taking geometry in high school.

It's Pi Day! The ratio of a circle's circumference to its diameter is rounded to 3.14, making March 14 the day to celebrate.

National Pi Day is recognized on March 14 in the U.S. and around the world. Here's what to know about the quirky holiday, and how to celebrate.

As math lovers know, it's Pi Day. And what better way to celebrate than by rolling out the dough? An NPR editor known for her experimental baking shares some of her favorite recipes.