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Answers: August 11

August 18, 2008

Problem: Geodetic and Control Surveys: State Plane Coordinate Systems

What approximation of the radius of the reference ellipsoid has traditionally been used as the basis for calculating the sea-level factor?

(A) 24,000,000 ft
(B) 20,906,000 ft
(C) 6,378,206.4 ft
(D) 20,925,620 ft

Answer is (B)
Solution: The mean radius of the spheroid over the coterminous U.S. has been considered as 20,906,000 ft for many years. This approximation is adequate for many applications, although the actual figure varies as much as 50,000 ft across the 48 states.

This is problem 51(9-28) from the new second edition of ”1001 Solved Surveying Fundamentals Problems” by Jan Van Sickle, PLS. Reprinted with permission from ”1001 Solved Surveying Fundamentals Problems” by Jan Van Sickle, PLS (1997, 728 pp., Professional Publications Inc.). For details on this and other FLS exam-prep books, call 800/426-1178 or visit www.ppi2pass.com .

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