Happy Pi Day!

It is that time of year again when we celebrate the beauty of a ratio without whom we could not find the area of a circle or the volume of a cylinder or cone.  It is found in nature but its also a number that government has tried to regulate via law or has been adopted by a military unit.

I am proud to announce that I have several T-shirts that deal in some for with that wonderful create we call Pi.  My students think I'm crazy but I'm just into math.

Its also a number that has been around for a very long time.  The ancient Babylonians took three times the square of the radius for the value of Pi but documents have been discovered showing they assigned a value of 3.125 for it around 1900 B.C.

Another document, the Rhind Papyrus from Ancient Egypt shows the Egyptians calculated Pi to be around 3. 1605 and this is still a fifteen hundred years BC.  Then around 200 BC, Archimedes, the famous mathematician, calculated the value of pi by using the Pythagorean theorem to find the area of a polygon inscribed inside a circle and a polygon with a circle inscribed within it.  He was able to show the value of Pi was between 3 1/7 and 3 10/71.

Even the Chinese had a mathematician who worked on calculating the value of Pi without being aware of the work done by Archimedes.  Zu Chongzhi came up with a value of 355/113 for Pi but we are not sure how he did it because much of his work has disappeared over time.

It took till 1706 for someone, namely William Jones, to assign the Greek letter Pi, the same one we use today to represent Pi but it did not become popular until Euler began using it in 1737.  Apparently, the letter was taken from the Greek word for perimeter. During the same century, a French Mathematician used probability to calculate the value of Pi.

Prior to computers, William Shanks, in 1874, calculated Pi to the 707th digit but only the first 527 were correct.  It wasn't until 1945 that D.F. Ferguson calculated Pi to 606 digits correctly.  In 1947, D.F. Ferguson used a table calculator to find the digits to 710 places.  With the computer, it became easier to calculate pi and has been calculated to over the 10 trillion places.

In addition, you'll find pi popping up in books, television, movies such as the Twilight series, in the Fox Trot series with the two young men, the Simpsons, cheers at MIT and Georgia Tech, colognes, and there is even music based on the digits of pi.  Its found in nature, in architecture such as the Pyramids, and its all around us.

I attend conferences where people wear t-shirts with Pi on it.  I have several and am proud to wear them.  Let me know what you think, I'd love to hear.  Have a great day.