ABSTRACT
This chapter discusses range of real-world situations and mathematical content, as well as all educational levels from primary to upper secondary school. It is devoted to a detailed exposition of a collection of modelling examples. In classroom experiments at school and university, the first approach by many students to solve this problem is a sketch of a right-angled triangle with the tower, a segment of the flat earth and the sight beam from the top of the tower to the other end of this segment. The example also shows that sometimes an established model can be used and extended to cover a more complex problem situation. Validating the model answers obtained consists in assessing how well these answers conform to the empirical reality.
