A plane is found by radar to be flying 5.9 km above the ground. The angle of elevation from the radar to the plane is 78.6°. Ten seconds later, the plane is directly over the station. Find the speed of the plane, assuming that it is flying level.

Answer 1

distance flown if level = d

tan 78.6 = 5900/d
d = 1190 meters in ten seconds
so
119 meters/second