Define:pi !!!!!!!!?

Question

Well before you answer ... I havent asked you for the value of 'pi' ..But what is a 'pi' .. And how come this number(3.14159265....) got introduced ... I mean whats so special about this number ???

Answer 1

Pi is the circumference of a circle with diameter 1. In general, if you take any circle's circumference and divide by its diameter, you get pi.

Mathematicians realized that all circles give this game number, so they gave it a special name.

Check out the wikipedia article, it has a sweet animation illustrating what pi is.

Answer 2

Pi itself is specifically defined as "the ratio of a circle's circumference to its diameter". So measure the distance around a circle, divide by the diameter, and you get Pi. It's been mathematically proven that this is always the same number, no matter how big or small the circle is, or what units of measurement you use. (In reality of course, we can't physically build a circle that's "perfect", or measure something without any degree of error. But using perfect shapes in a perfect world of Euclidean geometry, and strictly logical mathematical rigor, you can show that Pi is indeed a constant.)

So that's how Pi is defined. But oddly enough, Pi shows up in a number of other places such as the area of a circle, periods of trig functions like sine waves (which are ultimately based on the unit circle), etc. The proof of its irrationality and other properties have also led to other important proofs.

Answer 3

The number pi is special because it allows us to figure out the area, circumference, and many other things related to circles and arcs. In addition pi is not a rational number and has no repeating patterns. Pi is used in radians... I believe radians were first used to discover the circumference of a circle.

Answer 4

Pi is the length of the circumference of any circle divided by its diameter.