Linus Pauling's Hydrogen Atom: MVR=nh/2pi?

[The_ArtofScience]

I was reading Linus Pauling's "General Chemistry" when I noticed something that didn't quite fit. The angular momentum for the hydrogen atom was described as equivalent to n times h/2pi. Does anyone know why this statement is true? I've tried googling it and still can't seem to figure out how mvr= nh/2pi. The problematic part is the "n," how could you possiby denote a quantum number as anything but position?

 

[The_ArtofScience]

Nevermind, I found out how to get it!