2007-12-27 20:18:54 · 14 answers · asked by cseanc_79 2 in Science & Mathematics ➔ Mathematics
Pi is a ratio. It is the ratio of the circumference divided by its diameter. The number occurs so often for every circle that it was given its own number and Greek letter.
2007-12-27 22:28:39 · answer #1 · answered by james w 5 · 0⤊ 0⤋
The ratio of the circumference of a circle to its diameter is constant and this constant is called pi.
Its value is approximately 3.142 correct to 3 decimal places.
Note that this is an approximation. It value to 8 decimal places is 3.145159275 but even this is an approximation.
Pi is is an example of what is called an irrational number because its value cannot be expressed as a ratio of two whole numbers (integers).
This means that pi cannot be represented with perfect accuracy in any decimal notation. No matter how many decimal places weer use, we will still end up with an approximation to pi.
As to why it is ~3.142 rather than ~6.9852 there is no answer other than to say that is what it is because the ratio of circumference to diameter is ~ 3.142.
2007-12-28 00:05:49 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Pi is a physical constant that does not change. It is the ratio of the circumference of any circle to its diameter. In fact it also applies to spheres (volume) as well - anything completely round. Why the particular value 3.142....? Well, it's the way things are. Like Planck's constant, etc. Freaked out the Greeks too.
2007-12-27 20:35:17 · answer #3 · answered by Anonymous · 1⤊ 0⤋
It is an universal constant, it is the ration between the Circumference and the Diameter of *any* circle. So it depends on the definition of circle. As we all agree on the definition of circle than we have to agree on the value of π.
If you want a more "philosophical" answer it is the proof that non-integer number are as "natural" as integer ones, they are equally necessary to describe nature.
When computing the surface of a triangle you do basis*hight/2 You never wondered where the factor "/2" comes from, because it easy to understand. π is just the same but a bit harder to understand.
2007-12-27 20:28:10 · answer #4 · answered by paulatz2 2 · 4⤊ 0⤋
a Greek man found out that the circumference of a circle is 3.14159265... and pi=3.14159265... not 3.142
2007-12-28 00:24:31 · answer #5 · answered by damohxy 3 · 0⤊ 0⤋
There are several discussions on how the ancient greek mathematicians got this kinda value,some say the value was found in bible and the revealation by The Phoenicians
Check out these webisites to get more info
http://en.wikipedia.org/wiki/Gematria
http://www.purplemath.com/modules/bibleval.htm
2007-12-27 20:35:42 · answer #6 · answered by ::Ð嬢Y¢LøÞs:: 3 · 0⤊ 1⤋
Because it is the ratio between the diameter and the circumference of a circle.
2007-12-27 20:25:29 · answer #7 · answered by map 3 · 2⤊ 0⤋
Cos' it's the number that you get if you divide the circumference of a circle by its diameter, no matter what size the circle is.
2007-12-27 20:24:33 · answer #8 · answered by Anonymous · 2⤊ 0⤋
Its the number of times the diameter of any circle goes round its circumference. so if ur diameter is 3cm, the circumference wud be 3.14... * 3
2007-12-28 07:59:10 · answer #9 · answered by Ustadji 1 · 0⤊ 0⤋
Because a mad old Greek dude messed around with a few numbers and said it was. I bet even super maths scholars don't even know why.
2007-12-27 20:22:39 · answer #10 · answered by Anonymous · 1⤊ 1⤋