## Lesson 3: Curiosities and Jokes (IV)

November 19, 2010### The number Pi

The mathematical constant pi (π) is defined as the ratio of a circle’s circumference to its diameter. It is also the ratio between a circle’s area and its radius squared. It is approximately equal to 3.14159, but has been calculated to over one trillion digits.

### A Pythagoras’s student

The ancient Greek mathematician *Pythagoras* believed that all numbers were rational (could be written as a fraction), but one of his students *Hippasus* proved (using geometry, it is thought) that you could **not** represent the square root of 2 as a fraction, and so it was *irrational*.

However *Pythagoras* could not accept the existence of irrational numbers, because he believed that all numbers had perfect values. But he could not disprove *Hippasus’* “irrational numbers” and so Hippasus was thrown overboard and drowned!

# Jokes

Popular Pi Jokes

- Q: What do you get when you take the sun and divide its circumference by its diameter?
- A: Pi in the sky.

- Mathematician: Pi r squared”
- Baker: No! Pies are round, cakes are square!

Click on The “*Pi*” Joke and you will watch a funny animation.

Here you are pi song

If you are in the mood you can listen the complete version here .

See you!!

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