A circular celebration Mar 14, 2020

A circular celebration

It"s Pi Day, the day we celebrate the mathematical constant π. This day was chosen because today"s date, March 14, expressed numerically, matches the number"s first digits, 3.14. Pi represents the ratio of a circle"s circumference to its diameter. It can be used to compute the area and circumference of a circle, such as the circles that make up this bridge we"re looking at here in Copenhagen. (Who said math wasn"t useful in the real world?) Many people mark the day with activities based around mathematics—and most also serve pie. We can"t think of a more delicious way to study geometry.

© Lingxiao Xie/Getty Images

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Today in History

Mar 14, 2018Happy Pi Day!
Mar 14, 2019Rocky mountain pi
Mar 14, 2021Perfect timing
Mar 14, 2022Pi Day
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Mar 14, 2026Celebrating Pi Day

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