In Figure 19.19, slope distance S was observed as 19,875.28 m.The orthometric elevations of points A and B were 657.73 and 1805.54 m, respectively, and the geoidal undulation at both stations was -30.5 m. The instrument and reflector heights were both set at 1.50 m. Calculate geodetic distance A'B'. (Use an average radius for the Earth of 6,371,000 m.)
