Why are the solutions different?

[Albert Chan]

(02-29-2020 07:51 PM)tom234 Wrote:  When I enter the equation below into the Solver I get the answer:2,434.2929Statute Miles.
The same answer if I ented the for PPL program.
HMS-> entry goes to decimal form.
D=69.094*ACOS(SIN(HMS→(40.35))*SIN(HMS→(44.35))+COS(HMS→(40.35))*COS(HMS→(44.35)​)*COS((HMS→(75.1)-HMS→(123.16))))"

However, when I use My HP27s I get 2,426.9794 Statute Miles. This is correct for the formula backed up by my HP27s text.
This discrepancy or difference in the answer is quite distressing.

D seems to be calculated with latitudes 40.35°, 44.35°, longitudes 75.10°, 123.16°