# Why we celebrate National Pi Day

JACKSONVILLE, Fla. – Tuesday is March 14, also known as National Pi Day.

The celebration is based on the first three digits of pi, 3.14.

So what exactly is pi, often symbolized as the Greek letter π?

### A math lesson

π is considered a mathematical constant.

The basic premise of π is it represents the ratio of a circumference of a circle to its diameter.

This is achieved based the mathematical equation C/d where C is the circumference and d is the diameter.

This ratio is constant, regardless of the size of the circle.

The circumference of a circle is roughly three times the diameter, which is where the 3.14 comes from.

But it’s more complicated than that.

π is considered an irrational number. It cannot be expressed exactly and has no true end.

π out to 25 digits is:

3.141592653589793238462643

But it is usually estimated as 3.14 or 3.14159

π can also be a fraction of 22/7, but again that is an approximation.

### How it was discovered

The concept of π has been around for a very long time.

Some very early approximations of π have been discovered in Babylon and in Ancient Egypt. This was around 1900-1600 B.C.

π was formally calculated around 250 B.C. by the Greek mathematician Archimedes. In fact, π is sometimes referred to as “Archimedes constant.”

The constant was refined over the centuries since then. π was significantly refined in the 16th and 17th centuries through the advent of infinite series.

### Why is π so important?

π is one of the bedrock constants that mathematics and physics are based on.

π is used in numerous equations, especially in geometry and calculus. The constant is also found throughout other sciences, including physics, thermodynamics and electromagnetism.

Even weather forecasting can’t happen without π.

Without the concept of π, our knowledge of the world around us and how things work would be significantly reduced.

Many people celebrate π with pie!

The circular dessert is a great representation of π, as the mathematical constant holds true even in cooking!

So grab a piece of pie and celebrate the mathematics behind all that is π!