The purpose of this experiment is to measure the distance between 2 distant points using the triangulation method. First, the student performs the protocol on the law of sines. The method of calculating the lengths of a triangle can be used to measure very long distances: the Struve arc represents the largest triangulation network: it extends from Hammerfest in Norway to the Black Sea on a length of more than 2820 kms. The student can implement this method on a smaller scale, for example in the playground by trying to measure the greatest distance there. Before putting into practice and calculating the different angles with the theodolite, it is advisable to start by making a diagram on a sheet of paper by recording the different points that will be used for the measurements and viewing the video on the triangulation.