I kind of cleaned it up a bit (above).

Measure the control surface front to back. Let's say it's 4 inches. If the manufacturer says 10 degrees, type "4 sine 10" on your calculator and it will give you the travel in inches.

If your aileron is 3 inches and they say 20 degrees, type "3 sine 20" on your calculator, and the answer will your aileron travel in inches.

Again I think you might have to check if your calculator is in degrees and not radians.