It's Pi Day: 3.14.15 marks the celebration of a century

SEWICKLEY -- The numerical expression of the ratio of a circle's circumference to its diameter doesn't sound like a reason to celebrate.

But that number, which doesn't end or repeat, is a key to math, and if we didn't know about it, the world would be a lesser place.

3.14159265359 ... and on to infinity. More than a trillion of its digits have been calculated thus far, thanks in part to supercomputers and mathematicians who are mesmerized by its irrational and transcendental aspects.

Excited yet?

It's commonly called Pi after the Greek letter, a homonym with pie, the delectable dessert.

Saturday -- March 14, which can be expressed as 3.14 -- is Pi Day. What's more, it's the Pi Day of the century, because in this, the year 2015, it's 3.14.15.

It's as mouth-watering as a slice of homemade apple pie for math mystics.

"It only happens once a century, so it's pretty exciting," said Matt Michaels, chairman of the math department at Sewickley Academy. "We just try to take it as an opportunity to celebrate."

Even though Sewickley Academy students won't be in class on Saturday, at 9:26 a.m., they'll be exchanging emails to celebrate, because at that point they'll be able to express the first eight digits of Pi in the date and time of the email (3.1415926). Those with precise emailing systems could take it another level and send the email at 9:26:53 to more precisely mark the day.

"People have taken it to the extreme now by celebrating it," Michaels said.

But if a number aside from one that wins a lottery jackpot deserves to be celebrated, it's Pi.

"You wouldn't be able to build anything circular," without knowing Pi, Michaels said.

"All different cultures have tried to figure it out," he added.

It's the basis of geometry and is used in trigonometry, calculus, and even statistics, Michaels noted.

"It's more than just a number now, it's about seeing math in everyday life," he said.

Anyone who studies the STEM subjects -- science, technology, engineering and math -- is dependent upon Pi, according to Community College of Beaver County assistant math professor Beth Jansto.

And this is the only Pi Day of the 21st century where the numbers line up to reflect Pi so accurately, she noted.

"That does happen just once a century," she said.

For those wanting to celebrate the day with pie who want another reason to mark the moment, Saturday's also the 136th birthday for Albert Einstein, a true fan of Pi.