Simply put, pi is a mathematical constant that expresses the ratio of a circle’s circumference to its diameter. It figures into numerous formulas used in physics, astronomy, engineering and other fields, dating back thousands of years to ancient Egypt, Babylon and China.

March 14 marks National Pi Day, a celebration of the mathematical constant π (3.14) with freebies and deals. Here's what you need to know.

A Dunnellon staple since 1986, Front Porch Restaurant & Pie Shop offers "Stan the Man's Famous Fried Chicken," award-winning pies and a sense of home.

Pi Day is a favorite holiday for both food lovers and mathematicians. For the foodies, the reasoning is simple. Pi Day brings discounts and deals for people looking to grab a pizza to celebrate the holiday.

It's National Pi Day, so treat yourself to some pie — pizza, dessert or both, whatever your heart desires! That first "Pi" isn't a typo and differs from the tasty "pie" we eat, though we could easily draw some geometric similarities between the two.

Pi, defined as the ratio between the circumference of a circle and its diameter, is what's known as an irrational number. Despite its ubiquity, not only across math but also in fields as varied as medicine,