Happy Pi Day! 14 Saturday Mar 2015 Posted by Eric Hokanson in Math, Pi Day ≈ Leave a comment Tagsmath, mathematical constant, Pi, Pi day March 14th is Pi day, in honor of the mathematical constant, but this year is a once-in-a-century event: the year 2015 makes today’s Pi expansion, 3.1415! Yesterday at work we celebrated with Yep — a cherry Pi! Hooray Pi! three one four one five