Distance Along the parallel of latitudes

Any distance along any latitudes apart from the equator is taken to be on small circles.

The radius of the small circle in relation with the radius of the great circle is r = R cosα

Where α is the latitude’s angle.

Remember α for the equator is 0⁰ , hence at the equator r=R

Places are located at the point of intersection of both latitudes and longitudes angles e.g. Y (20⁰N,50⁰E)