# What Is Pi?

Have you ever heard of pi? No. I am not talking about an apple pie or a chocolate pie.

Pi is a number that never ends. It goes on and on and on…

In fact Pi = 3.1415926535…

Even all around the world March 14 (March – 3) is celebrated as a PI Day! And it is also Albert Einstein’s birthday. Isn’t it amazing! Yeah, PI is a magical number.

Now, you might be thinking what’s great about this number?

If you divide the circumference of any circle by its diameter, it is always equal to the same value and that value is called PI.

PI = (Circumference of Circle) / (Diameter of Circle)

PI is represented by a symbol π. This symbol is chosen because the Greek word for “periphery” meaning circumference begins with the Greek letter π. You might not be using π yourself every day, but π is used in most calculations for building and constructions, quantum physics, communications, music theory, medical procedures, air travel, space flight, and many more. In fact, the list is endless. In basic mathematics, it is used to calculate the area and volume of figures like a circle, sphere, cylinder, cone, etc. and also used in trigonometry. You might imagine that NASA (US Space Agency) regularly uses π to calculate trajectories (path) of spacecraft.