Take it from someone who knows. Z as the sum of D and L , from the SS Theorem. Z will therefore be larger than both D and L . D and the observer are in different hemispheres. L is the sum of D and Z , from the SS theorem.
L is greater than each D and Z .
D and the observer are in the same hemisphere. The observer is farther from the equator than D is. D is the sum of L and Z , from the SS theorem. D is greater than each L and Z . D and the observer are in the same hemisphere.