As briefly introduced in Chapter 1, engineering and surveying structures are set out (established) either on a plane earth or in space (where a sphere/ellipsoid defines the system). This chapter focuses on the plane system exemplified by the Australian Map Grid (MGA) system and shows you how one can convert measured angles to metric units in what is called join calculation (i.e., from rectangular/metrics to polar (bearings)). Given coordinate differences, one is expected to obtain bearings. This is often necessitated by the fact that during setting out in the field, one used already known coordinates (points) and as such needs to use them to establish bearings (directions from true north) to the points to be set out. The chapter shows how this can be achieved using a calculator. In chapter 4 we introduced formulae that are used to solve general triangles. In this section we will attempt to draw together all the material so far covered to help solve more advanced surveying problems.