Example.

With a surveyor compass the angles observed in traversing the lines AB, BC, CD, DE and EF are  as. Compute the included angles and indicate them in a neat sketch.

Solution: Given figure shows this traverse. The first back bearings of all lines are calculated and noted in the table shown below:

∠B = 55° 30′ + 63° 30′ = 119° 00′       Ans.

∠C = 63° 30′ + 70° 00′ = 133° 30′       Ans.

∠D = 70° 00′ + 45° 30′ = 115° 30′       Ans.

∠E = 45° 30′ + 72° 15′ = 117° 45′        Ans.