On Pi Day, How Scientists Use This Number | NASA JPL

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The world celebrates the number pi on Pi Day: March 14, 2015 (3/14/15). Here’s how pi is used in science and engineering.

If you like numbers, you will love March 14, 2015. When written as a numerical date, it’s 3/14/15, corresponding to the first five digits of pi (3.1415) — a once-in-a-century coincidence! Pi Day, which would have been the 136th birthday of Albert Einstein, is a great excuse to eat pie, and to appreciate how important the number pi is to math and science.

Pi is the ratio of circumference to diameter of a circle. Any time you want to find out the distance around a circle when you have the distance across it, you will need this formula.