ARI SHAPIRO, HOST: Pick a number, any number.</s>CHRIS FLINK: You know, you can go 3.1415926535897...</s>SARAH MCCAMMON, HOST: I think I hear pi.</s>ARI SHAPIRO, HOST: 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.</s>SARAH MCCAMMON, HOST: 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.</s>CHRIS 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.</s>ARI SHAPIRO, HOST: The Exploratorium, where Flink works, has been hosting Pi Day events since that first one in 1988.</s>SARAH MCCAMMON, HOST: Back then, they had a pi processional and a circle led by the late physicist Larry Shaw. They also ate fruit pies.</s>ARI SHAPIRO, HOST: 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.</s>CHRIS 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.</s>SARAH MCCAMMON, HOST: Happy Pi Day, everybody.
Chris Flink is executive director of the Exploratorium in San Francisco, otherwise known as the birthplace of Pi Day. He speaks about the importance of the holiday that celebrates the ratio of a circle's diameter to circumference.