how did some greek guy come up with the idea of pi?

Answer 1

Someone noticed that the ratio of circumference to diameter for any given circle was always constant... about 3.14... Over the years, as measuring devices became more accurate, the value of that ratio was more and more precise. 22/7 is one approximation, 3.14 is another. 3.14159 is better. Computers have now calculated pi to many thousands of digits.

Answer 2

In two similar figures of any kind the ratio of corresponding linear measurements is constant. So in all squares the ratio of the side to a diagonal will be the same no matter the size of the squares.

And how do we measure the distance (perimeter) around a square. We use a side s and the perimeter can be "seen" to be P = 4s so the ratio of the perimeter of a square to its side (you could even call it the diameter) is P/s = 4. You might even say that for a square Pi = 4.

For an equilateral triangle the ratio of perimeter to side is
P/s = 3.

Now Greeks were thinkers so it occurred to one or more of them (and even peoples such as the Iraqis before them) to ask if there is a "side" or other linear measurement of a circle that could be used to measure the circumference. Of course the diameter of a circle is a natural linear measurement for a circle.

If you inscribe a circle inside a square of side S, then since the circle is inside its perimeter is less than that of the square so we casn begin by saying that pi < 4,

Next, someone figured out how to inscribe a regular hexagon inside a circle. The perimeter of the hexagon is P = 6s where s is the side of the hexagon and But notice that s of the hexagon is exactly the radius of the circle, so P = 6s = 6r = 3d where d is the diameter of the circle and so P/d = 3. But since the hexagon is inside the circle its perimeter if less than the circumference of the circle so now we have

3 < P/d = C/d < 4

Continuing the inscribing and circumscribing procedure your Geek Greek honed in on a pretty accurate4 value for pi./

Answer 3

I don't actually KNOW historically.

But it probably went like this:

1. They decided that the area of a circle was proportional to the square of the radius. They decided this by approximating the area of a circle by polygons, each of whose areas was DEFINITELY proportional to the square of the radius.

2. They gave the proportionality constant a name.

Answer 4

I think he just needed a name for that very odd proportion between diameter and circumference, and picked a letter.

The idea itself is simply a description of that proportion.

Answer 5

Hunger.

Answer 6

he's GREEK!!!