Eli5: I always thought pi is 22/7, but recently i found out that 22/7 is a number that is pretty close to pi, not pi itself. Then how do mathematicians found more “pi” ?

Question

Eli5: I always thought pi is 22/7, but recently i found out that 22/7 is a number that is pretty close to pi, not pi itself. Then how do mathematicians found more “pi” ?

In: 167

Answer 1

A very old method makes use of the definition of pi: the ratio between the circumference of a circle and it’s diameter. You can use a polygon with many sides as an approximation of a circle. The more sides it has, the closer to pi you get.

For example, using a hexagon (6 sides) gives you a value of 3. 12 sides give about 3.11.

Nowadays, there are faster methods, but with those, it is not as obvious as to why they work.