Pi Day

Pi Day: Getting to Know Pi

Nerd Out

What is π?

The number

**circumference **of a circle to its **diameter.**

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Get active

Use the Internet to find out which came first -

Constant but Irrational

It does not matter how big or small the circle is,

We say that 3.14 is an approximation of

The first known method for rigorously calculating better and better approximations of

To date, we have calculated the first 62.6 trillion[1] digits of

By the way, here are the first 40 digits of

3.141592653589793238462643383279502884197

Pi is central to a great deal of mathematics. It crops up in all sorts of interesting places, not just those involving circles and spheres. One example is if you add up all the fractions where the numerator is one and the denominator is a perfect square, the answer turns out to involve

^{2} ^{2}/

More practically,

Watch the video called The infinite life of pi (3:44) for an excellent summary of this extraordinary number:

[1] https://www.popularmechanics.com/science/math/a37329769/supercomputer-calculated-pi-to-record-breaking-628-trillion-digits/

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22.4 trillion digits of pi

Visit https://pi2e.ch/blog/2017/03/10/pi-digits-download/ to learn more about the world record computation of π. You can even download all 22.4 trillion currently known digits. Just note that this is not the most digits of π that have been computed. That record is currently 62.8 trillion.

Discover π

If you are new to

- Take any of the round objects available and measure the length of the object’s circumference (that’s its outside edge). A good way to do this is to lay a piece of string carefully along the edge and then to lay the string along a ruler. Write this number down.
- Now measure the diameter (the straight line that passes through the center of the object from one side to the other). Write this number down.
- Use a calculator to divide the length of the circumference by the length of the diameter. What answer do you get? Is it about 3.1?
- Now repeat the above steps with as many other round objects. What number do you get at the end each time?

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Digits of Pi

Mathematicians and math enthusiasts have spent many hours looking through the digits of

Other interesting π resources:

Why is Pi so special?

This video briefly explores some of the strange places

A surprising Pi and 5

This video explores a fascinating link between the number 5 and

The Discovery That Transformed Pi

Attempts to calculate π ever more accurately has driven important advances in both mathematics and computer science. This video explores one of these advances.

Explanation of pi and its importance

A short explanation of why π is so important.