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.

WHAT IS PI? Pi can calculate the circumference of a circle by measuring the diameter — the distance straight across the circle's middle — and multiplying that by the 3.14-plus number.

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.

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.

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.

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. Jana Frank, a franchise owner of Mathnasium, shared some ways to celebrate Pi Day.

WHAT IS PI? Pi can calculate the circumference of a circle by measuring the diameter — the distance straight across the circle’s middle — and multiplying that by the 3.14-plus number.

What is Pi? Pi can calculate the circumference of a circle by measuring the diameter — the distance straight across the circle’s middle — and multiplying that by the 3.14-plus number. It is considered ...