**Doing Math for Spheres**

**Helpful Formulas and Definitions**

**r = radius**

**Surface area of a sphere = 4 * pi * r^2**

**Volume of a sphere = 4 pi r^3**

** 3**

**Circumference = 2 pi r**

**pi = 3.14159**

**from mark**

**G = gravitational constant
== 6.672*10 E-11**

**Mass of earth +5.98 * 10E24**

**Time that it takes for a satellite to orbit
the earth (in seconds -- IT MUST BE A SMALL SATELLITE)=**

__ 2pi
__ * THE SQUARE ROOT OF R(in
meters) CUBED

**square root of the gravitational constant
* the mass of the earth in KG**