Basic geometric-trigonometric equalities and problemsolving: Angular Elements
This paper presents some equalities that we consider useful for the resolution of general high school level geometry problems. The presented equalities involve only angular elements. The objective of this work is to monitor, on a small scale, the skills and knowledge acquired by students in the eleventh year of school in an Italian region named Apulia. This goal has been done by mean of different exercises where 21 students were asked to recognise and combine the equalities presented. Results are reported and discussed.