Whenever anyone says **pi(π)**, what is the first thing that came to your mind? *“Oh *yaa* Pi, It is 3.14 or just 22/7!”* But have you ever thought why this **3.14** holds such importance? Why this number only. Why this 22/7 has endless numbers after the decimal point? Why this pi(π) is used to find the area or circumference of a circle? Why not any other number, let’s say 5.38 or 7.19. Now we will dig deeper into this thing and will talk about the significance of Pi today.

### First of all, what is pi and what it is used for?

**Pi** equals the circumference divided by the diameter of a circle. **Pi** (π), *the 16th letter of the Greek alphabe*t, is **used** to represent the most widely known mathematical constant. By definition, **pi** is the ratio of the circumference of a circle to its diameter.

*Now you must be thinking what if *we* change the diameter of the circle, will the value of pi change?*

The answer is * NO*! It doesn’t matter how big or small the circle is – the ratio stays the same. If a circle has twice the diameter of another circle it will also have twice the circumference. I think now you got the point. Seems interesting!

To have a closer illustration of pi look at this picture:

**Take a circle whose diameter (all the way across) is 1. If you roll it until you get back to the start, it will measure out Pi units.**

### Now why this constant is used in every formula? There you go!

The number Pi appears routinely in equations describing fundamental principles of the universe, due in no small part to its relationship to the nature of the circle and, correspondingly, spherical coordinate systems. Pi is a constant in formulae to do with circles and spheres. E.g. Pi is defined as the ratio of a circle’s circumference to its diameter,or as the ratio of a circle’s area to the area of a square whose side is the radius.

### What about the invention of pi(π).

*Pi is not strictly speaking an invention.* If anything, it is a discovery of something God created. Now onto the discovery. That the ratio of the circumference to the diameter of a circle is the same for all circles, and that it is slightly more than 3, was known to ancient Egyptian, Babylonian, Indian and Greek geometers. The Indians and Greeks also knew that the area of a circle is **πr2**, where r is the radius. But who assigned the name “Pi”? It would make sense that it is a Greek.

### Value of pi(π)

* Pie is a constant whose value never ends and never settles into a permanent repeating pattern*. Ancient researchers were able to calculate the value of pi only around 7 digits after the decimal using geometrical techniques.

In 1949, Ferguson and Wrench computed ** 1,120 digits** using a desk calculator. The first computer attempt, in 1949 on the ENIAC (the first general-purpose electronic computer),

*. By 1967, the record stood at*

**took 70 hours and computed 2037 decimal places***, and in 2009, Takahashi et al. used a supercomputer to compute*

**half a million digits***of Pi. But it didn’t stop there.*

**2.5 trillion digits**The first computational results used massive computers. But on the last day of 2009, Fabrice Bellard used a home computer – running an Intel Core i7 CPU to compute * 2.7 trillion* places. And the most recent record of

*of Pi was computed by Alexander J. Yee and Shigeru Kondo in 2011 using a fast, but not crazy, dual processor Intel Xeon-bsed machine with a huge amount of hard disk space.*

**10 trillion digits**