Question

the coordinates of a point relative to a reference point are given as (1km, 6km, 2km) of the cylindrical coordinate system was employed calculate the longitude angle corresponding to this point

Answer 1

The relationship between Cartesian and cylindrical coordinate systems is as follows
x=r cos⁡〖φ, y=r sin⁡〖φ, z=z〗 〗
Thus, the longitude angle
φ=arctan⁡〖y/x=arctan⁡〖6/1=80.5°〗 〗