Help me with (c) please

Two fire-lookout stations are 190 miles apart, with station a directly south of station b. both stations spot a fire. the bearing of the fire from station a is upper n 55 degrees upper e and the bearing of the fire from station b is upper s 60 degrees e. how far, to the nearest tenth of a mile, is the fire from each lookout station?

Answer question above and explain each step : )

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)