Ignore me, I'm stupid

In order to get this 3d engine running correctly, I need to find the angle of a given point off of the main axis. Not a problem... except I need inverse trig functions to do that. Again, not a problem. I found a site that I copied inverse sine and cosine functions from... perfect. Except that both of them require inverse tangent, which I can't find a function for... leaving me back at square one. All I need is that function and I'll be good. Or another way of determining angles from the Y axis...


EDIT: I looked... it's built in to VB... I didn't figure that because none of the other inverse functions are... but Oh well.