Abstract

Suppose you are stranded on an island and you want to get over to the nearby mainland. Your only option is to swim. But is the other shore close enough? If you embark and it isn’t, you drown. So you prefer to know before taking off. Happily, you are well equipped. You have not only a yardstick, but also a theodolite for measuring angles, and a good knowledge of trigonometry. You then determine the distance to the other shore by means of triangulation. You fix two points, A and B, on your own shore, and identify a third point, C, in sight on the opposite shore. You then measure the distance between A and B with your yardstick, and the two angles ABC and CAB with your theodolite. With this information you can calculate the distances AC and BC to the other shore.