(a) What is the corrected project elevation if the instrument has a sight line that inclines at the rate of 0.5mm per 50 m?

(b) What is the estimated error in the elevation difference?

(c) What is the 95% error in the final established benchmark?

A tilting level is used to run a set of precise levels to a construction project from benchmark DAM that had an elevation of 536.103 m. The line is run along a road that goes up a steep incline. To expedite the job, backsight distances are kept to 100 ± 2m while foresight distances are 40 ± 2 m. The total length of differential levels is 4480 m. The elevation difference observed is 36.819 m. The instrument’s level is centered to within ±0.3" for each sight and the rod is read to ±0.5mm per 50 m.