The Area of the Disk in Middle School Grade by GeoGebra

Abstract

The visualisation and exploration of mathematical objects and concepts in multimedia environments can facilitate learning. Geometry is particularly involved with the growing use of software in teaching. GeoGebra is a dynamic geometry system that increases the level of knowledge and skills in mathematics. The use of GeoGebra permits one to complete and extend a teaching strategy based on manipulative activities. The area of a disk in Middle School, i.e. Grades 7–8, offers the opportunity to use a large amount of geometry dynamic software. This paper proposes, as an example of combining in between manipulative activating and dynamic geometry software, the use of GeoGebra to permit the visualisation of three different approaches to the area of a disk. The first one is based on the limit of the area of inscribed regular polygons, the second one is based on dynamical morphing of the disk in a triangle and the third on sampling methods.