Oh dear...
I know Gary knows this, but others may not. The trigonometry functions in
some calculators use radians rather than degrees (so instead of dividing a
circle into 360 degrees, circles are divided into 2pi radians, or about
6.283 radians.) So if you tried this on your calculator and got 0.1106 yada
yada, and might be wondering what you or Gary did wrong, then you have your
answer.
Some calculators let you specify units up front. You can also ask google to
do the work for you: if you enter "arctan(1/9) in degrees" without the
quotes, you'll get the answer in degrees as Gary suggests. If you're not
near google or really love your calculator, you can convert radians to
degrees by multiplying by (360/6.2832) or 57.295 to get the right answer..
And if that don't do it for ya, Lost Art Press sells something that I think
is called a Bevel Monkey that will help you set your bevel gauge to
specific angles. It is helpfully labeled in degrees.