Saturday, March 14 is not just Pi Day this year. It’s the first five digits of Pi in the standard date abbreviation 3/14/15.

Pi is the symbol used in geometry to represent the ratio of the circumference of a circle to the circle’s diameter. You can use it to find the area of a circle, which is Pi times the radius of the circle squared.

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When calculated, Pi continues past its decimal place infinitely and with no pattern or repetition - 3.14159265359…

"Pi Day is always celebrated on March 14," WHIO meteorologist Kirstie Zontini explains, "but this year it is a special event."

“Look at 10 digits of Pi (3.141592653), then look at the clock Saturday, 3/14/15 at 9:26:53! The date and time line up with the digits of Pi. A Pi Day like this happens once a century."