orthodromic distance:
the shortest distance between two points P, Q on the surface of the sphere of radius R
if we know  longitude (east-west position),  latitude (north-south position)  of P and Q
Write the values in the boxes.  Then press    -  Clear all:
lon P = °    lat P = °

lon Q = °
   lat Q = °

R =

DIST. = 


=   A
(you can use "A" as one or both inputs)
storage area:
If you have to put a coefficient using some other function symbol (for example √2; π/2), put it in a numerical form (1.414213562373095, 1.5707963267949), for example using this (or this).  [NaN = "not a number"]