Image made with elements from Canva. It’s March 14, or Pi Day, that day of the year where we celebrate the ratio that makes a circle a circle. The Greek letter that represents it is such a part of our ...

This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated. Math enthusiasts around the world, from ...

Happy Pi Day! The annual celebration, held every March 14, is your chance to pay tribute to the most famous constant in math and physics: the number you get when you divide the circumference of a ...

Pi, a mathematical constant denoted by the Greek letter π, is the ratio of a circle's circumference C to its diameter d: π = C/d. The circumference of a circle is, in turn, equal to 2πr, where r is ...