# All About Pi

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Category: Education

By: Sarah

## Presentation Transcript

### All about PI:

All about PI By Sarah Mallek

### What is PI?:

What is PI? Pi is the circumference of a circle divided by the diameter of that circle. It’s the same value for any sized circle, no matter how big or how small. We use the symbol π to represent it.

### What is PI?:

What is PI? Using this circle as an example… C/d = 40.5/12.89 = ? Divide these numbers = 3.14197 Very close to pi?

### Numbers of PI:

Numbers of PI These are the first 100 digits of PI.  3. 1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679

### History of PI - Babylonians:

History of PI - Babylonians Pi has been known for almost 4,000 yrs. The Babylonians (1900 BC) calculated the area of a circle by taking 3 times the square of it’s radius, which gave a value of pi = 3. They also estimated pi to be 3.125 which is a closer approximation.

### History of PI - Egyptians:

History of PI - Egyptians The Egyptian writing Rhind Papyrus (1650 BC) showed that the Egyptians used the number 3.1605 to find the area of a circle.

### History of PI - Getting Closer:

History of PI - Getting Closer Archimedes of Syracuse (287 BC) approximated the area of a circle using polygons inside a circle. He approximated pi to be between 3 1/7 and 3 10/71 (3.14084) Zu Chongzhi (429 BC - China) also approximated pi to be 3 16/113 (3.14159)

### History of PI – 1700’s:

History of PI – 1700’s M athematician William Jones began to use pi (π), a letter in the Greek alphabet. It was made popular by another mathematician Leonhard Euler (1737) George Buffon, a F renchman, made a way to calculate pi based on probability.

### Real Life Applications:

Real Life Applications One real life application is figuring how much corn you can put into a silo. You use pi because you have to calculate the volume of a silo(cylinder) which has a circle as base.

### Real Life Applications:

Real Life Applications Planetary Scientists use pi to find the volume of a planet (sphere) V = 4/3 π r 3 . They use this to tell what kind of planet it is by its density (mass divided by volume)

### Works Cited:

Works Cited http://www.exploratorium.edu/pi/history_of_pi / http ://pinotpie.weebly.com/what-are-some-examples-of-pi-and-how-is-it-used.html http ://lightyears.blogs.cnn.com/2012/03/13/pi-day-how-3-14-helps-find-other-planets-and-more /