A lighthouse is visible just above the horizon at a certain station at sea level. If the distance between the station and the lighthouse is 50 km, what is the height of the lighthouse? (Take the correction coefficient for combined curvature and refraction as 0.06735)

A contouring of a reservoir site was surveyed and the following data was found: Contour (m) : Area enclosed (hectares)620 : 23625 : 112630 : 425635 : 910640 : 1200 Calculate the total volume of water impounded using the Prismoidal formula.

A fore bearing angle in a whole circle bearing (WCB) system was measured as 165°. What is the relation used to find the back bearing angle of the line?