posted by Jake .
You are stationed at a radar base in Warner Robins, GA and you observe an unidentified flying object at an altitude of 2000 m flying towards your radar base at an angle of 20 degrees. How far away from the radar base is that plane (hypotenuse)?
Once you made your diagram, and let the hypotenuse equal to h, this becomes a basic case of solving
sin 20º = 2000/h for h