The length of a baseline measured on ground at an elevation of 300m above mean sea level is 2250 m. The required correction to reduce to sea level length. (given the radius of earth is 6370km) is _______.

The required slope correction for a length of 60m, along a gradient of 1 in 20 is

Differential levelling is carried out from point P (BM: +200.000 m) to point R. The readings taken are given in the table.

Reduced Level (in meters) of the point R is ____ (rounded off to 3 decimal places).