A map of a certain area is drawn on a sheet. The distance on the map is 1 dm and that on the ground is 5 km. The representative fraction for the given data is _____________. (Note that 'dm' means decimetre.)

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?