Algebraic thinking in geometry at high school level: Students’ use of variables and unknowns

Abstract

The research was carried out over a three-month period in two high schools in the United States. The six focus students who were selected to participate in the study were asked to solve some problems in geometry requiring the use of variables and unknowns. It was found that some of the difficulties that the students had were generic ones that students usually have in algebra but that others were mainly due to a poor understanding of the underlying geometrical or algebraic concepts.