Hellow Fellow Readers! What day is today?! If you are Mathematician, Physicist, Engineering, Chemist or something related with the Science you should know.. IT π DAY!! a day to commemorate that great infinite transcendental number that describes the ratio between any circle’s circumference to its diameter. So it deserves a day.. ! Watch this content related to the amazing π constant.

To begin, the first Geeks that calculated π were the Egyptians and Babylonians around the year 1900 BC. The calculation for π made by the Egyptians were the number 256/81 and the Babylonians 25/8, both within 1% of the true value. Besides that, the Indian text Shatapatha Brahmana gives π as 338/108 which is 3.139, a very nice approach.

*Egyptian Papyrus of Rhind with some math quotes*

Archimedes was the first one to estimate π rigorously, he realized that its magnitude can be bounded from below and above by inscribing circles in regular polygons and calculating the outer and inner polygons respective perimeter. Using the equivalent of 96 sided polygons, he proved that

< \pi < 3\tfrac{10}{70}." /> The average of these values is about 3.14185. This is called the Method of Exhaustion.Then came some chinese development to approximate the π value, and more serious investigators like Madhava of Sangamagrama, Gottfried Leibniz, John Wallis, Isaac Newton, Leonhard Euler, Ferdinand von Lindemann, among many others researchers, but was John Wrench with a gear-driven calculator in 1948 that got the most accurate estimate of π before the electronic computers came into use, with 1120 decimal digits!.

With the coming of electronics, progress in the calculations of digits was not only due to faster hardware, but also new algorithms. One of the most significant developments was the discovery of the Fast Fourier Transform (FFT) in the 1960s, which allows computers to perform arithmetic on extremely large numbers quickly. (Yeah Fourier ROCKS in LOTS of ways.. !!! we can hear digital music thanks to you too :D).

*Computer animation used to demonstrate the geometric concept of π.*

The best approximation is recorded for Shigeru Kondo, using an 2x Intel Xenon X5680, 3.33 Ghz and has 5.000.000.000.000 decimals!! achievement got it on 2010. Just to notice.. in 2009 Fabrice Bellard using a Core i7 CPU of 2.93 GHz and a RAM memory of 6 GiB got 2.699.999.990.000 decimals, if we analyze this machine, is not a very big deal! I bet that some of the readers has computers very similar as this one!

The PI number is used in Geometry and Trigonometry, Complex Numbers and Calculus, Physics, Probability and Statistics, Geomorphology and Chaos Theory (Yeah Ian Malcom from Jurassic Park comes to my mind anytime that i hear about Chaos).

After all this background about pi.. we got how he comes into our lives, things, geek stuff and calculus, but let’s hear now how does it sounds like !!