Happy Pi Day! We celebrate **Pi Day** (3-14) as a pop culture holiday, meant for exploring and having **fun with math**. It centers on the mathematical constant we’ve come to love.

Everyone knows about Pi, but no one knows definitively what it is. It is identified as 3.14 but mathematicians have calculated it to **more than a trillion digits**. Pi Day began as an celebration in **San Francisco**, organized in 1988 by physicist Allan Shaw. He invited the staff and members of the public to march around one of the **San Francisco Exploratorium**’s circular spaces, stopping to eat fruit pies along the way. In 2008, the **U.S. House of Representatives** declared March 14 **National Pi Day**.

Pi (π) is the ratio of a circle’s circumference to its diameter. Pi is a constant number, meaning that for all circles of any size, Pi will be the same. The diameter of a circle is the distance from edge to edge, measuring straight through the center. The circumference of a circle is the distance around.

March 14 also happens to be **Albert Einstein’s birthday**. So eat pie, throw some pies, or celebrate in some circular way. Thank you, Dr. Shaw.