please help with AOB

OK so I can now get the angle of bow to input but im not sure I understand what the numbers mean on the dial. for instance Im doing the sub school torpedo lesson and got a angle of 49 degrees If I remember correctly and when I go to the dial there isn't a 49 lol how do you come up with what number it is ? Ive watched lots of tutorials on how to get the angle but they don't explain what it transfers to lol.