EGITIM ARASTIRMALARI-EURASIAN JOURNAL OF EDUCATIONAL RESEARCH, cilt.9, sa.35, ss.147-164, 2009 (SSCI)
Problem Statement: International studies, such as the repeat of Trends in International Mathematics and Science Study and Programme for International Student Assessment, have shown that the mathematics achievements of Turkish students are lower than the international average. Geometry is an area of particular weakness. The use of dynamic computer environments has been advocated as a means to improve student understanding and problem-solving skills in geometry. Although a number of research studies have utilized dynamic geometry software as a tool for investigating students' learning of geometrical concepts, most are case studies with very small samples of students. Therefore, there is a need for experimental studies about the effects of dynamic geometry environments on students' learning of various geometrical concepts.