Dynamic Geometry Software (DGS) is an important technology that develops enriched teaching and learning environments, because the instrumental characteristics of this software are appropriate to accomplish the internalisation process of incorporating mathematical knowledge (Mavrotheris, Mavrotheris & Maouri, 2004, p. 115).

Dynamic Geometry Software includes packages such as Cabri Geometre, the Geometer’s Sketchpad and Thales. These enable users to define objects such as points, lines (or segments, rays and vectors) and circles (or arcs) and to construct geometric objects by classical constructions (straight edge and compass), linear transformations (translation, rotation, dilation, reflection) and/or algebraic relationships using coordinates (Cartesian and polar). Measurements may be made, on which computations can be performed and from which other objects can be defined. Loci of moving points and envelopes of moving lines can be defined and drawn, and such curves will change shape instantly as adjustments are made to their defining objects (parameters).

Reference:

Mavrotheris, E., Mavrotheris, M., &  Maouri, C. (2004) Towards a More Constructive Use of Technology in Mathematics and Science, 115-116.