I need to know how to calculate what percentage of a number is to another.

Question

let me make that clearer, 35 is what percent of 48? how is that calculated?

What you are asking is this:

35 is to 45 as x is to 100
or

35/48=x/100
solve for x
x=.729
Now to get % you must multiply x by 100 to get 72.9%

Plese try this link:
http://amby.com/educate/math/4-2_prop.html

Why is the theorem called the pythgorean Theream?