# Pi Day is Silly, but Serious

March 14 is celebrated as “Pi Day” around the world. Inspired by the first three numerals in the irrational number pi, 3.14, the holiday celebrates mathematics, circles, and pie.

Pi, represented in mathematics by the Greek letter π, is an infinite number used to calculate the area of circles and other curved shapes.

As far as anyone can tell, the first official Pi Day celebration occurred in 1988 at the San Francisco Exploratorium. The simple ratio of a circle’s circumference to its diameter, however, was discovered by ancient Babylonians.

According to the book, “Infinite Powers: How Calculus Reveals the Secrets of the Universe,” it was the Greek geometer Archimedes, some 2,300 years ago, who first showed how to rigorously estimate the value of pi. He started by making a hexagon out of straight lines inside a circle. By multiplying the number of lines by the length of each one, he was able to estimate the circumference of the circle.

As more lines are added, the interior shape more accurately conforms to the shape of the circle. Think of each decimal added to the end of pi as another leg in that shape, endlessly becoming more perfectly round.At this point, computers have calculated the value of pi out past 22 trillion digits and counting. To get a visual on one million digits, click here.

Even mathematicians love a good pun, so Pi Day isn’t all math. Celebrations often involve delicious circular pies also, from lemon meringue to pizza.

Try this one out on somebody today:

Why is it unwise to talk to pi?

Because it will go on forever!