ARI SHAPIRO, HOST:
Pick a number, any number.
CHRIS FLINK: You know, you can go 3.1415926535897...
SARAH MCCAMMON, HOST:
I think I hear pi.
SHAPIRO: That's Chris Flink, executive director of the Exploratorium in San Francisco. The interactive science museum is the birthplace of what has become a global holiday.
MCCAMMON: That's right. Check your calendars. It's March 14 - 3-1-4 - Pi Day. If you remember your lessons, pi is the mathematical constant that comes from dividing any circle's circumference by its diameter.
FLINK: It's a number that allows us to compute all sorts of things in the world. Revealing its consistency across all circular and spherical forms that occur in nature and in engineering allows us to kind of produce all kinds of important mathematical results.
SHAPIRO: The Exploratorium, where Flink works, has been hosting Pi Day events since that first one in 1988.
MCCAMMON: Back then, they had a pi processional and a circle led by the late physicist Larry Shaw. They also ate fruit pies.
SHAPIRO: Thirty years later, pi pilgrims - that's P-I - are flocking to the Exploratorium, so there's a lot more pie. That's P-I-E. Flink says more than a thousand slices will be served.
FLINK: I personally really enjoy blueberry pie. Others argue that cherry pie is superior. But really any sort of pie would be appropriate, particularly a round pie.
MCCAMMON: Happy Pi Day, everybody.
(SOUNDBITE OF MJK'S "PI AS MUSIC") Transcript provided by NPR, Copyright NPR.