2. An airplane is 50,000 m above an observer and 2.1 km to the west of them and 1.5 km to the north of you. Determine the angle to the plane in the x – y axis and the total distance to the plane from you. Choose the x-axis east, y axis north, and z axis up
If the problem was presented in this language, that's some poor textbook!
The distance d (in km) of the plane from you?, me?, them? might be
d^2 = 2.1^2 + 1.5^2 + 50^2
In the x-y plane, the angle is
arctan(1.5/-2.1)