Happy International Pi Day: Here Are 11 Intriguing Facts about Pi

Pi is both naughty and nice. Find out why.
Christopher McFadden

Happy international "Pi Day" everyone! In celebration, here are some interesting facts about this naughty "irrational" number.

Bask in the glory of one of the most interesting and useful mathematical concepts ever devised by mankind. You lucky, lucky person you.


What are some interesting facts about Pi?

So, without further ado, here are some interesting facts about Pi. Trust us when we say this list is far from exhaustive and is in no particular order.

1. The symbol for Pi was actually introduced by a Welshman

facts about pi symbol
Source: geralt/Pixabay

Wales has a lot to be proud of. Great singers, great sportsmen, cawl, welsh cakes, a flag with an actual dragon, legendary archers, a beautiful countryside, and a rich history. 

But there is one lesser-known piece of Welsh history that needs to be celebrated a lot more. It turns out that the very symbol for Pi was first introduced by a Welsh mathematician called William Jones in 1706.

That's right, "boyo!"

The symbol has now been in use for well over 250 years but was actually popularised by another mathematician, Leonhard Euler. 

2. We will never be able to accurately calculate the area or circumference of a circle

As useful as Pi is as a mathematical concept, it is not perfect. The exact value for Pi can, famously, never actually be calculated in full.

This is because Pi is what is called an irrational number. This means that the number of decimal places for Pi is, in fact, never-ending. 

It can't be expressed as a proper fraction that has a definitive end. 

For this reason, it just keeps going and going forever. In fact, to date, Pi has been calculated to over 22 Trillion digits.

Because of this, it follows that we could never truly calculate the circumference or area of a circle. We can only make a "best guess." 

3. It was once attempted to round up Pi using the force of the law

facts about pi law
Source: Woody Hibbard/Flickr

Have you heard the story of the time that it was attempted to round up Pi using the full force of the law? Well, it actually happened back in 1897.

One Indiana doctor attempted to make it law to round Pi from 3.14 etc. to 3.2. He argued that this would solve all the problems of its irrational nature and simplify future calculations that depended on the value of Pi.

Dr. Edwin Goodwin proposed a bill to the state legislature and also copyrighted the idea in hopes of claiming royalties if he was successful. The bill was duly debated, but most of the delegates believed that using the law to change a mathematical concept was inappropriate, to say the least. 

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The bill failed. 

4. There is actually a language based on Pi

Did you know there is actually an entire language based entirely on Pi? Called Pilish, the numbers of letters in successive words match the digits in Pi.

Mike Keith, a devote Pilish-lover, even wrote an entire book in Pilish called "Not a Wake." 

5. Some chap recited Pi to an incredible 70,000 decimal places

Back in 2015, one chap actually managed to remember and recite Pi to 70,000 decimal places. The legend, Rajveer Meena of VIT University, Vellore, India, took no less than 10-hours to achieve the feat.

In order to preserve his concentration, Mr. Meena wore a blindfold throughout the duration of this epic challenge. An absolutely amazing achievement.

6. Pi is not a new concept -- not by a long shot!

facts about pi pyramids
Source: sculpies/iStock

Pi is actually a very old concept. The first recorded evidence of its existence was around 4,000 years ago in Ancient Egypt and Babylonia.

Like today, the ancients had discovered a magical ratio between the circumference of a circle and its diameter to be equal. The size of the circle was not important, but they always appeared to get the same answer -- roughly 3.14.

Because of this, it became part of Egyptian mythology. In fact, it is still believed today that the pyramids of Giza were built on the very principles of Pi.

"The vertical height of the pyramids have the same relationship with the perimeter of their base as the relationship between a circle’s radius and its circumference." - piday.org.

7. Pi might not be that useful

facts about pi not useful
Source: Rex Sorgatz/Flickr

The very fundamental practical use of Pi has been in debate for quite some time. Despite being loved by many math enthusiasts, and us at IE, love might indeed be blind.

Some Pi-heathens believe that tau (2π) might actually be better suited for circle calculations. This is because you can, for example, multiply tau with the radius of a circle to calculate its circumference more intuitively.

Tau divided by 4 also represents the angle of a quarter of a circle very effectively. Of course, they could be evil Pi-hating maniacs.

8. The Chinese were well ahead of Europe with regards to Pi

Long before the Europeans hit on the concept of Pi, the Chinese were already well aware of it. The simple reason for this was the fact that they had invented the concept of zero well ahead of their European counterparts.

They also had invented decimal notations ages before Europe. 

It would not be until the middle ages that European mathematicians would develop anything on par with Chinese ones. At this time, Europe would be reintroduced to their ancient Greek and Roman intellectual heritage, and Arabic and Indian influence on mathematical concepts, like zero, into their mathematical systems.

9. This chap actually hand-calculated Pi to 707 digits -- but made a mistake

facts about pi hand calc
Source: Robert Couse-Baker/Flickr

Back in 1873, on man, William Shanks, worked tirelessly to manually work on the digits of Pi. He spent many days and nights, over several years, trying to calculate the digits of Pi as far as he could.

Shanks managed, incredibly, to find the first 707 digits all on his own. 

Sadly for Shanks, he actually made a mistake on the 527th digit. This meant that all other digits after this were completely wrong.

That must have really ruined his day. 

10. "Pi Day" has some interesting connections to famous scientists

facts about Pi Einstein
Source: United States Library of Congress Prints and Photographs Division/Wikimedia Commons (Edited)

Further to point 9 above, this day appears to have some interesting real-world connections. As it turns out, the 14th of March is both the birth date of Albert Einstein.

It also happens to the day that the late, great, Stephen Hawking passed away.

Spooky right?

11. Forget the Pi-haters, practicality is pretty awesome

While it is pretty impressive to recite Pi to x decimals, like Rajveer Meena mentioned above, for some calculations, the more decimals you use, the better. For every-day things like the circumference of a balling ball, for example, using Pi to 70,000 decimal places is not really practical. But when it comes to larger stuff, it can indeed be critical.

As you scale up to something like a galaxy, the more decimal places you can use the more accurate your calculations. But not by that much.

If, say, you were to just use the first 9 digits of Pi to calculate the Earth's circumference, it is better to use more than less.

For every 25,000 miles (40,234 km) or so, the use of 9 digits would only give you an error of around 1/4 of an inch (0.635 cm)But let's get a little more ambitious, the most distant object man has ever sent from Earth is Voyager 1.

This probe is about 12.5 billion miles (31.75 billion km) away from us. If you plotted an imaginary circle at that distance, it would be about 25 billion miles (63.5 billion km) in diameter.

By using Pi to just 15 decimal places to calculate the circumference of that circle, your result would only be out by around 1.5 inches (1.27 cm).

That is incredible -- Long live Pi!

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