The Design and Implementation of Intersection Points of Geometric Figures in NetPad

It is a very important function of dynamic geometry software to construct intersection points of geometric figures. However, this function isn't perfect in most dynamic geometry software yet. In this paper, we design and implement intersection points of geometric figures in NetPad, an advanced online dynamic mathematics software designed for teaching and learning mathematics in elementary and secondary school. Under the design concepts of convenience, completion and stability, NetPad not only can conveniently construct intersection points of any geometric figures, but also maintain the continuity and stability of intersection points. Through some teaching cases, we demonstrate the simplicity and efficiency of constructing intersection points of geometric figures in NetPad.