**Pi π Day **

It’s March 14 — 3.14 — which also makes it Pi π Day! Pi, represented by the Greek symbol (π), is part of the formulas for calculating the circumference and area of a circle.

However, Pi is an indefinite number, with 3.14159 being its closest approximation. Pi has been known for almost 4,000 years—the ancient Babylonians, Egyptians, Greeks, and Chinese devised various approximations of its actual value.

You might not care about Pi or even think it applies to you, but you might be surprised. Pi is used in most calculations for building and construction, quantum physics, communications, music theory, medical procedures, air travel, and space flight, to name a few. And if you are counting daily steps toward your 5,000, you might want to know how far you walk. For example, if you walk around a circle that has a diameter of 100 feet, multiply that by Pi and you’ll find you’ve walked approximately 314 feet. In this example, the circle’s area is the ratio of its circumference (314 feet) to its diameter (100 feet).

So what does Pi have to do with Pie? It’s a homonym. Pi Day started in 1988, the brainchild of Larry Shaw, a staff physicist, tinkerer, and media specialist at San Francisco’s Exploratorium science museum. On the first March 14th π Day, at 1:59—the π numbers that follow 3.14—Larry and his wife, Catherine, set up a table on the museum’s floor topped with fruit pies and a tea urn for the celebration. π Day became an annual Exploratorium tradition for staff and the public, and the idea snowballed. Now it’s celebrated by math lovers and educators worldwide. In March 2009, π Day became an official U.S. national holiday, celebrated with π themed activities and antics, and of course with lots of pie!

We’ll mention in passing, that π Day is also the birth date of the famous mathematician and physicist Albert Einstein, born on this day in 1879. So Happy Birthday, Albert Einstein! We’re celebrating with some π.