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.

Pi Approximation Day occurs every July 22nd. It celebrates pi, a key mathematical constant. Pi relates a circle's circumference to its diameter. William Jones introduced the π symbol in 1706 ...

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'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 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.

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.