60) What is the difference in level if back sight of reading 3.370m inter sight of reading 2.975m?

61) What is the correction for curvature for a distance of 10km (Correction of curvature =0.0785D²)?

62) What is the correction for curvature for a distance of 800m (Correction of curvature=0.0785D²)?

63) What is the correction for refraction for a distance of 5km (Correction of refraction =0.0112D²)

64) What is the correction for refraction for a distance of 800meters (Correction for refraction =0.0112D²)