Question

What is the number pie

Answer 1

`\pi-\bold{pi}\\\\\pi\ \text{it's the ratio of a circle's circumference to its diameter}\\\\\pi=\frac{\text{circumference of a circle}}{\text{circle diameter}}\\\\\pi\ \text{it's irrarional number}\\\\\pi=3.14159265358979323846264338327...\\\\\text{Approximation of}\ \pi:\\\\\pi\approx3.14\\\\\pi\approx(22)/(7)\\\\\pi\approx(355)/(113)`

The number pi occurs when calculating the surface area or volume of the rotational solids.

Cylinder:

`S.A.=2\pi r^2+2\pi rH\\\\V=\pi r^2H`

Cone:

`S.A.=\pi r^2+\pi rl\\\\V=(1)/(3)\pi r^2H`

Sphere:

`S.A.=4\pi R^2\\\\V=(4)/(3)\pi R^3`

The number pi occurs when calculating the area and the circumference of a circle.

`C=\pi d=2\pi r\\\\A=\pi r^2`

It is also used to convert angle measure in degrees to radians.

`x^o=(x\pi)/(180)\ rad`

Answer 2

You meant pi, pi is a irrational number, but they use 3.14 for approximation, so that is your answer.

Hope this helped!

Nate