subject : fundamentals of surveying
Extracted text: 21. The elevation above sea level of two end poits of a base line for a triangulation system, as determined by differential leveling, are: 2,683.45m and 2,615.22m. Determine the mean sea level length of the line if the actual measured horizontal length is 5,525.850m. Assume the radius of the earth at the vicinity of the base line is 6, 423.349 km. a) 5523. 571m b) 5513.454m c) 5509.678m