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National Pi Day (March 14)

Check out the weird holiday National Pi Day on March 14. Learn the history of National Pi Day, and get ideas on how to celebrate.

One weird holiday on March 14 is National Pi Day. Check out the other weird March holidays!

History of National Pi Day

Pi is such a special number! It is an irrational number (meaning it goes on forever and never ends or repeats itself). Pi is often rounded to 3.14, which is why it is celebrated on March 14.

Pi Day was founded in 1988 by the physicist Larry Shaw. Pi is approximately 3.14159265, so some people will even celebrate Pi Day on March 14th at exactly 1:59am (or pm, for those who do not like to wake up in the middle of the night).

Shaw handed out fruit pies and tea at 1:59 at the Exploratorium in San Francisco beginning in 1988. He wanted to have a fun celebration to bond the Exploratorium staff together. A few years later, Shaw’s daughter Sara pointed out that March 14 was also Albert Einstein’s birthday.

On March 12, 2009, the United States Congress declared Pi Day an official national holiday.

Pi Approximation Day is on July 22nd, which is when countries who format their days at day/month celebrate Pi. That is because the fraction 22/7 is very close to the value of Pi.

Pi is the relationship between a circle’s circumference (the distance around the circle) to its diameter (the distance across the circle through the middle).

Basically, if you take the diameter of a circle and multiply it by the value of Pi, you will get the circumference.

The knowledge of Pi’s existence has been around since around 2,000 BC when the Egyptians and Babylonians used it to build. Over the centuries, mathemeticians like Archimedes (in the 3rd century BC) and Fibonacci calculated Pi using different methods.

The first person to use the Greek letter π that we know of to represent Pi was William Oughtred in 1647.

In 1706, William Jones began using the Greek letter π (pi) to represent the ratio of a circle’s circumference to its diameter. Jones was a Welsh mathemetician.

Later in 1737, Leohnhard Euler began using the symbol.

You can also use Pi to calculate the area of a circle with the equation A= πr2 (pi times the radius squared). You can remember this equation with a silly joke: why shouldn’t pie be baked as a circle? Because pie aren’t round, pie are square! (Pi r squared)

Ideas for National Pi Day

You can do any of these Pi Day Crafts and Activities for Kids, or any of the ones below:

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