In inches, every pin is 1/2" from 1 to the next. so a 44 t = 22" and so on.........

My math skills aren't the best, but that would give you the circumference right?

Let's assume a 28" sprocket - I don't think it's diameter would be 14". I just measured the one I have and it's between 4 and 5" (hard to measure on a bike with the cranks on).

Circumference = Pi (Diameter)?

So, Circumference/Pi = Diameter?

So, a 28 tooth sprocket would have a circumference of 14" and a diameter of 4.46"? (28/3.14)?

That seems about right.