Draw and label a typical three-wire leveling setup

C. Leveling Rod L₁ FS Leveling Rod - BS BM, HI, TP₁ Elev. of TP, Leveling Rod Horizontal Line of Sight BS + Difference in Elev. between BM and BM₂ Elev of BM, (known) (Do not copy the illustration or drawing) Table: Determination of Elevation STATION BS HI FS ELEVATION BM1 1.60 m 100 m TP1 1.47m 0.85 TP2 1.67 m 0.78 TP3 1.54 m 0.89 BM2 0.75 COMPUTATIONS: 1. Computing Height of Instrument and Elevation. In differential leveling, the following two (2) equations are repeatedly used a.) HI Elev + BS b.) Elev=HI-FS Where: HI = height of instrument above a reference datum (MSL) BS = backsight reading on the rod (or plus sights) FS = foresight reading on the rod (or minus sights) ELEV elevation above datum of a point sighted FS BM₂ Elev. of BM₂