Graphical representations of geometrical objects from high school textbooks are categorized according to the implicit conventions underlying their display. The fact that specific illustrations can lead to students' misconceptions about geometric objects is analyzed in relationship to the principle of parallel projection with implications for the…

Secondary school geometry students have been found to have misconceptions concerning parallel lines. Correctional teaching programs did not seem effective in changing these misconceptions. This research describes an attempt to use teaching strategies which take into account current learning theory and which encourages students to be actively…