Ah, sorry. I thought you had said you were using CAD. If you're doing it by hand then maybe that would be the way to go, though I think using a protractor would be much easier and more accurate.
I need to learn trig......
And I just didn't understand what they were for, I guess I didn't ask my question clearly enough. The reason I want to know how far apart the are with a given radius is so I can space them along the circumfrence of the barrel centers evenly. Unless anyone has a sugestion on how to do that.
I am using cad... I guess you mean there is some way to do it on the software, I guess I'm not familiar with it then.