## The mystery of pi

Pi is a mathematical mystery that’s captivated people for thousands of years. There’s even an entire holiday dedicated to this mystery, called Pi Day (which is on March 14). There are numerous ways to celebrate Pi Day, from cracking pi jokes to learning more about the never-ending number. We couldn’t believe some of these fascinating pi facts – how many do you know? Read on to unlock parts of the mystery.

## People have been using pi for thousands of years

Pi (the Greek letter π, pronounced like the word “pie”) is the ratio of the circumference of any circle to the diameter of that circle, explains maths instructor Steven Bogart. It equals roughly 3.14. No matter what size a circle is, the circumference will always be 3.14 times bigger than the diameter. Over 4,000 years ago, the ancient Egyptians and Babylonians had figured out this constant and were using it to make calculations. In the 18th century, mathematicians gave the number the name “pi.”

## We celebrate pi on March 14

Back in 1988, Larry Shaw of San Francisco’s Exploratorium science museum started observing March 14 – get it? 3/14! – which also happens to be Albert Einstein’s birthday, as Pi Day. By 2009, the celebration had grown so big that US Congress passed a resolution to make the designation official. The resolution states: “The House of Representatives supports the designation of a ‘Pi Day’ and its celebration around the world … and encourages schools and educators to observe the day with appropriate activities that teach students about Pi and engage them about the study of mathematics.” In another stamp of approval, in 2010, Pi Day got its own Google Doodle.