Today is Pi Day, a time to celebrate the never-ending number that helps us calculate the ratio of a circle's circumference to its diameter.
Here in the U.S., Pi Day has officially become a "thing" — for example, today at Whole Foods, you can get slices of pie for $3.14, and if you can solve math problems from a Princeton professor, Pizza Hut will give you 3.14 years' worth of free pizza.
The developing world, which we cover in this blog, loves its pi, too.
Suresh Kumar Sharma, a 21-year-old former vegetable vendor from Jaipur, India, is the current record holder on the Pi World Ranking List when it comes to reciting the digits of pi. In October 2015, he recited 70,030 numbers in 17 hours. To do it, he associated every number with an image. Now he helps coach others in their memorization skills.
The Guinness World Records, however, says the top pi reciter is Rajveer Meena from India who reeled off 70,000 digits in just 10 hours in 2015 while blindfolded.
(Meanwhile, a 69-year-old Japanese man says he's the unofficial record-holder, claiming he can recite about 111,700 digits.)
Here's a roundup of global pi facts, past and present.
- An Egyptian scribe named Ahmes was one of the first to record the value of pi, around 1650 B.C. On the famous Rhind Papyrus, a collection of math problems, Ahmes wrote, "Cut off 1/9 of a diameter and construct a square upon the remainder; this has the same area as the circle." According to his calculation, pi equaled 3.16. That's just about 1 percent off the modern 3.14 number and closer than what the Chinese were using hundreds of years later: pi = 3.
- Over time, global math gurus have made pi more accurate. In the year 480, the Chinese brought pi to six digits. In 1400, Indian scholars helped push it to 11 digits. Thanks to computers, we're up to 13.3 trillion digits today.
- In India, a Sanskrit verse gives the value of pi up to 31 decimal places. Numbers are translated into alphabetical code — for example, "ka" represents 1, "ra" for 2, "gha" for 3 and so on — and strung together. The verse doubles as a hymn to Lord Krishna.
- The top five spots in the Pi World Ranking List, a global list of people who can recite the most pi digits by heart, belong to India and China.
- A couple of Namibian kids got special notice from the list in 2007 for reciting 30 decimal points ... while juggling three balls.
Know of any more facts about pi around the world? Share them with us in a comment below or tweet them at @NPRGoatsandSoda.