Abstract:
Teaching mathematics is no longer the act of teaching already-made mathematics, but
rather starting from real-life problem situations, modeling, exploring, analyzing and
hypothesizing. This study develops and pilots an instructional unit on Thales‟ Theorem that
applies the guidelines of constructivist approach, counts on problem solving and reasoning
skills (inductive and deductive), and integrates the use of Dynamic Geometry Software
(DGS), namely Cabri Geometry, in teaching and learning. The study, comparing control
and experimental groups, aims to investigate the effect of a DGS-based Constructivist
Approach (referred to as DGS-CA) on students‟ motivation, geometric problem solving
abilities, and learning achievement. The participants are grade 9 students learning under the
Lebanese Mathematics Curriculum in two private Lebanese schools. The total number of
participants is 32 students, 24 boys and 8 girls. The study used qualitative and quantitative
methods to examine the effect of DGS-CA; an interview to investigate teaching methods of
the control group’s teacher, a questionnaire to test for motivation, and two tests to examine
the effect on achievement and problem solving skills. Results showed that DGS-CA had a
positive effect on students‟ motivation to learn mathematics and on students‟ mathematical
achievement, however this effect was non-significant. On the other hand, DGS-CA had a
significant effect on students‟ geometry problem solving skills, more specifically on their
proving skills.
