ABSTRACT
Hexagons or any other polygon (a closed shape with straight edges) can be constructed by adding triangles together. Thus, if the properties of triangles are understood, any other polygon can also be dealt with. Triangles are ideal for purposes such as mapping, since there is a simple set of rules relating the lengths of their sides to the size of their angles. Angles, in geology, are normally measured in degrees since this is a convenient unit for measuring dips, strikes and other similar quantities. However, there are other units which can be used of which radians are the most important. This chapter uses the sine, cosine and tangent functions, which are collectively known as trigonometric functions. Geological cross-sections frequently have different scales in the vertical and horizontal directions since data may be mapped over several kilometres horizontally but only extrapolated downwards for a few hundred metres. The most common vector operation (vector addition) is discussed.
