Happy Pi Day! Posted on March 14, 2012 by Tony Caselli Today: 3/14 Pi: 3.14 π (sometimes written pi) is a mathematical constant that is the ratio of any Euclidean circle’s circumference to its diameter. π is approximately equal to 3.14. Share this: Share on X (Opens in new window) X Share on Facebook (Opens in new window) Facebook More Email a link to a friend (Opens in new window) Email Share on LinkedIn (Opens in new window) LinkedIn Share on Reddit (Opens in new window) Reddit Like Loading...