# Pi Day

March 14, 2018 happens on a Wednesday this year. The Americans denote this calendar day as 3.14 not 14.3 as we do. Incidentally 3.14 also coincides with the first 3 letters of that magnificent number Pi and is denoted by the Greek letter “π”. Pi is used in mathematics to represent a constant — the ratio of the circumference of a circle to its diameter and it approximately equates to 3.14159… Pi goes on, and on, and on because the number is irrational, which is the reason it intrigues me.

The Americans, love pomp ceremony and celebration. This in in my humble opinion explains their success. Cry a lot, laugh a lot, celebrate a lot, to unite in adversity. So they cobbled Pi Day, with class and mind-set, only they have. The winner, off course, is mathematics through the children’s love of this concept. Pi Day is now a huge event on the school calendar which even President Obama was obsessed about.

How is Pi day celebrated? Glenville-Emmonds High in the USA looked at what 1,000,000 digits of Pi looks like on a word document. They sing pi songs, tell pi jokes, and recite pi poems. They also have a pi digits memorization contest, to see who can memorize the most digits of pi. The student with the most digits memorized is awarded the official pi-day gold medal.

How many numbers have been memorized? Akira Haraguchi, 69, holds the record of being the first human to memorise Pi to 100,000 digits. He then recited these digits in a 16-hour marathon in 2006, pausing only for 5 minutes every two hours. On another Pi Day, 14 March 2015 or 14.3.15, the first 5 digits of Pi, he recited Pi to 111 700 digits. This is also the date that I had my first Pi Day in South Africa, with Khethiwe Nkuna, now lead CSI at Accenture SA.

Ferguson, back in 1945, laboriously determined the longest (till then) and the most accurate calculation of Pi without the use of a computers. He calculated Pi to 808 digits, by hand. Pi has since been calculated to trillions of digits its decimal point through computers. Pi is called an irrational and transcendental number, because it will continue infinitely without a repetitive pattern.

Human civilizations became aware of Pi as early as 2550 BC when pyramids were built based on Pi computations. The ancient Greek mathematician Archimedes (287-212 BC) is considered to be the first to calculate an accurate estimation of the value of pi. In the 15th century, Indian mathematician Madhavan calculated pi to 11 decimal places.

I love people who spend productive time counter-intuitively. As Mr Miyagi said “Man who catch fly with chopstick accomplish anything.” So it is that Peter Trueb, a Swedish scientist chased the rainbow for this pot of gold. He computed Pi to 22.5 trillion places after 105 days of around-the-clock computation, using some serious hardware and the Chudnovsky algorithm.

So what can we use all these extra digits for? Not much! NASA only uses around 15 digits of pi in its calculations to send rockets to space. To get an atomic-precise measurement of the universe, you would only need around 40 digits. So computing trillions of digits of pi is basically about showing off computer power.

The reason Pi is not a random number is due to the fact that the digits, and their positions are determined and fixed and computable. The second decimal place in Pi is always 4, the third decimal place is always 1. Pi’s digits are therefore not randomly positioned. If no digit of an irrational number appears more frequently than any other when written as a decimal, it is called “normal”. Is Pi normal or does some digits appear more often than others. Trueb did anecdotally find that Pi is indeed “normal”. Twenty-two trillion digits seems like a good sample to test Pi., Trueb examined what the distribution looked like. “Each of the numbers from nought to nine appeared 10 per cent of the time, which is what you would expect if pi is normal,” says Trueb. Trueb’s nickname is Pipi which he swears has nothing to do with Pi. Right.

We need SA need to build this culture of celebrating these kind of events, with gusto. This year Mymoena Ismail, the CEO of NEMISA enthusiastically agreed to celebrate Pi Day with me in Nelspruit with pie, pizza perhaps even a pina colada. I will also celebrate Pi Approximation day with a few schools on 22 July later this year. Its 22/7. Google this day as your homework.

Want to try an experiment with your kids? Get your child to bring a bowl. Turn the bowl upside down. Now place a string around the bowl which you measure. Now get them to measure the diameter of the open bowl, which is the longest point across. The division will be rough value of Pi. Get them to try this on a different sized bowl.

Worried that AI and robots are going to take over the world? Let’s just do what Dr Spock did. He commanded an evil computer to compute Pi to the last digit! This it cannot do, because, as Spock explains, “the value of pi is a transcendental figure without resolution.”

Want to have some fun? Google “The Pi-Search Page” and click the link. Type your birthday. My birthday expressed as a 6 digit birthday as in MMDDYYYY format appears only twice in the first 200 million digits! Speaking of birthdays, March 14 also happens to be Albert Einstein’s birthday. I just might put a candle in my Pi(e) for him on Pi Day. This however is relative.

**Dr Colin Thakur is a digital activist who is committed to the dream of “one person, one connected device.” He is the KZN e-Skills CoLab Director, located at the Durban University of Technology. His areas of research include e-democracy, Social media, and unstructured big data.**

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