Dr. H. Vogel - Zentrum Mathematik - Technische Universität München

Use of CINDERELLA in higher elementary geometry

DGS group ICTMT5
Klagenfurt 6.-9.08.2001

0. Introduction

This paper shows the possibilities of presenting advanced Euclidean Geometry on an HTML-page with the interactive geometry software CINDERELLA. It deals with the well known WALLACE-line and a generalization of this line invented by O. GIERING.
I prepared this matter as HTML-pages for an in-service training course for teachers this year. This pages begin with a very simple question on high school level. Than we continue with some related problems slightly above this level. At the end we consider a generalization on an advanced level and get envelopes and curves of higher orders. You can see this lecture "Around the WALLACE-lines" at: http://www-m1.ma.tum.de/lehrer/material/elementargeometrie. There you will find another lecture on "DGS at school" and a "Workshop with various DGS", too.

This lecture is divided in the following chapters

1. Illustration of well known geometry facts using the move mode and the animation mode

2. Discovering of new conjectures doing interactive exercises

3. Creating the envelope of a set of straight lines
4. Construction of conics determined by certain conditions

5. Creation of algebraic curves of higher order