what on earth is pi?!?

Question

well I know what it is. 3.14. and I know what you use it for. but how did they come up with it?!

Answer 1

Outstanding question. I can try to explain but I won't do justice. You can look around for "history of pi" on google/wikipedia. I guess I can get you started on "how it was found"

It seem to have originated through its use in building architectural units (houses/domes/etc). The fact that the ratio of the circumference to the diameter of a circle is constant has been known for so long that it is quite untraceable.

Here's a simple exercise that you can do, that I think someone back in gazillion BCE must've done. just draw a circle. take a string and "line-up" with the circumference. Now cut that exact piece (which has length of circumference), and now take another string and cut a portion that stretches through the diameter of that circle.

now put these two pieces of strings on a side. Do the same for a few different sizes of circles. and compare the diameter (or radius) with circumference for circle 1, circle 2 and so on. be surprised!

Hope this helps

Answer 2

Lets start out with a circle with a diameter of 1. Now lets place this circle in a square. Since the side length of a square is equal to the diameter, the square's side will be 1 (it helps to draw a picture). So lets find the perimeter of the square. The perimeter is going to be 2*1+2*1=2+2=4

So the perimeter of the square is 4. Since the square is much larger than the circle, it's perimeter is larger. If we construct a pentagon around our circle (with all sides touching the circle and find the perimeter, we will find that the perimeter will decrease. As we increase the sides of the polygon, the perimeter decreases. Basically our perimeter is starting to approach some number as we go on forever and it eventually will become about 3.14. Basically our polygons will eventually become close enough to be considered a circle and will have the same perimeter (or circumference) as our circle. Notice how the formula for the circumference is:

C=pi*d

Since our diameter is 1 we have

C=pi

Notice our circumference is pi which is what the perimeter of our polygons slowly become.


This technique was known to the ancient Greeks. Now we have many techniques to calculate pi to about a few million digits.

Answer 3

Isaiah 40:22 Circle = Circuit = circumference. Ie, the outer ingredient. The circuference of a globe is the circuit around its ingredient. this would not mean that circle ability a 2 dimensional merchandise, as a circle of a globe remains a three dimensional ingredient. a million Kings 7:23 And he made a molten sea, ten cubits from the single brim to the different: it replaced into around all approximately, and his top replaced into 5 cubits: and a line of thirty cubits did compass it around approximately. would not say something approximately Pi in there. The thirty cubit compassing bit refers back to the outer circle, yet a cubit isn't exatly a widespread length. A cubit is 'relating to the size of a mans arm from elbow to finger suggestions'. subsequently, making an allowance for various lengths of palms could be quite a few diverse sizes. Thirty cubits isn't 3. that's thirty. enable for the irregularities interior the cubit measurements you get the rought length not a 'scientifically top' one. In those days, they weren't as pedantic approximately their measurements and stuff as we are right this moment.

Answer 4

http://www.humboldt1.com/~cbender/chris/Pi2.htm

A link with some history on PI. I wish I had a $1 for each time I've used PI or 3.14 in all the computations. I've taken 37 hours of college math and used it somewhere in all except Linear Algebra. Don't recall using it there.

Answer 5

It is the ratio of circumference to diameter.
You use it to calculate circumference and diameter of circles. Also, for the volume of spheres, circular cones, etc. just anything related to a circle.

In trigonometry, you learn about radians, which they are usually (but not always) expressed in terms of pi in the unit circle.

Answer 6

Pi is the ratio of the circumference of a circle to its diameter

pi = circumference / diameter

π = symbol

π is a irrational number

π = 3.141592654. . . .is a nonrepeation non terminating decimal goes on to infinity.

- - - - - - -s-

Answer 7

Nobody came up with it. It's just a property of our universe. There was a guy in Chicago in the 1920's who came up with an alternative called Whi, but everytime he built a wheel with it, it came out square.

Answer 8

it's the ratio of the circumference of a circle to it's diameter. pick any circle in the entire universe, use the ratio circumference:diameter, you will always get pi - 3.141592653 etc etc.

Answer 9

It's the ratio of the circumference to the diameter of any circle.

Answer 10

fttp://mathforum.org/dr.math/faq/faq.pi.html
Check -out this web site. It has history and derivation on Pi.