Slide 1: All About Pi Created by Jan Abernethy
March 2006 What is Pi? : What is Pi? Pi is defined as the ratio of the circumference to the diameter of a circle
Pi is usually denoted with this greek symbol:
p p = circumference diameter What is the “Value” of Pi? : 3.141592551104866223558431126381048812355898112276391048823661691 12648104891237105711355110577023712221136511058672371277113652105 86823713861136671058762371496113682105891237171611369410589123723 75113696105806987498576984769847609873409867439857694387569803475 28937465283974658927364587923645897236458723645987236859742365298
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Mathematicians estimate digits of pi to use it in real world settings. Click here to find digits of pi.
Pi is usually rounded off to about 3.1415 History of Pi : History of Pi The hunt for pi began in Egypt and in Babylon about two thousand years before Christ. The Egyptians obtained the value (4/3)4 and the Babylonians the value 3 1/8 for pi. About the same time, the Indians used the square root of 10 for pi. These approximations to pi had an error only as from the second decimal place. Who Discovered Pi? : Who Discovered Pi? Archimedes was the first to theoretically approximate pi
He calculated that pi was “trapped” between 223/71 and 22/7, or roughly 3.1428
Today we use better approximations, most of which are derived by computers Slide 6: The Death of Archimedes Archimedes was born in 287 BC in a Greek state called Syracuse, Sicily.
The city of Syracuse was taken over by the Romans and Archimedes was killed.
It is said that he was busy drawing circles in the dust and writing mathematical equations at the time of his death THAT’S HOW IMPORTANT PI WAS TO ARCHIMEDES!!!!! Slide 7: Currently the value of pi is known to 6.4 billion places! The Usefulness of Pi : The Usefulness of Pi Pi is extremely useful in calculating the area and circumference of a sphere: A = pr2 and C = 2pr.
Many disciplines of science use p in their equations to describe the world
In fact DNA, rainbows, the human eye, music, color, and ripples all have some natural roots in pi. Slide 9: Let's review some
DEFINITIONS Diameter and Radius : Diameter and Radius The distance across a circle through its center is called its diameter, D.
The radius, R of a circle is the distance from the center of a circle to a point on the edge of the circle.
So a circle's diameter is twice as long as its radius: D = 2 × R. diameter, D radius, R Slide 11: radius Slide 12: diameter Slide 13: C i r c u m f e r e n c e The distance around a circle is its circumference Slide 14: p = Pi = circumference divided by diameter Every time you use these formulas, you will come up with
3.14159265… Slide 15: The space inside a circle is called the Area Slide 16: I drew polygons of more than 90 sides! Take it from me… the area of a circle is pr2 Slide 17: APPROXIMATELY The symbol means When speaking of pi we always use Example: p 3.14 Slide 18: LET’S REVIEW THE FORMULAS! Slide 19: SOME NAMES FOR PI 3.14 22 7 ___ pi p Hope you enjoyed
learning about Pi!!!