## Happy Pi Day!

A simple ratio should be celebrated today, the ratio that rounds off to 3.14. It is simply the ratio of the distance around a circle to the longest distance across a circle. But it never really ends as far as we know.

But importantly, March 14th, when expressed in numerical form is 3/14 which corresponds to the common approximation of pi that is common in the United States. Of course calculators now store more digits, but for most of us, rounding off to 3.14 just feels right.

Several other approximations have been used  like 22/7 or 355/116. The former is only good to two spaces, but the latter makes it to six places.

Larry Shaw kicked off pi day in 1988 making this the 26th year of 3.14 celebrations. Engineers are nerds, but they do know how to have fun. Congress recognized March 14th as a national pi day in 2009. Now we can all join in a bit of geeky fun. Some have celebrated memorizing pi to 67890 digits.  Chao Lu of China took 24 hours and 4 minutes to spout the number. It took so long that they had to use more than one video tape.

Most of us would use a protractor to even draw a circle, but computers draw circles all the time or rounded arcs. Consider this page and the number of round or curved shapes their are in the text alone. All of these use a calculated value of pie to place the pixels, but here’s the rub: how in the world do you get to a calculation of pie?

Calculating a square root is fairly easy even without a calculator. It takes running through the calculation a number of times, but it’s basically summed up in the following.

x1 = n-(1-n/x)/2

That’s not all that bad, just keep plugging in the new value for x until x1=n. You can even modify the equation to calculate other roots. But never mind this for now. Pi is more difficult. After looking at several examples, I found myself even more lost than normal.

Math is Fun didn’t really give an answer, it just said to draw a circle with a radius of one. This is hardly a calculation you could do in your head like my little way of figuring out square roots on road trips. This little article is certainly more useful to a computer programmer, but not useful to the idle dabbler.

As is proper these days of wikipedia and other open source sites, I found myself on wikihow. Which explained the infinite series argument a little better than the previous article. But it didn’t get at the development of the concept. Maybe next year for Pi day, I’ll try a bit harder.

Until then, I just need to find a vegan form of pi… or pie.