摘要:AbstractThe purpose of this study is to determine the effects of dynamic mathematics software GeoGebra on student achievement in teaching of trigonometry. The sample of the study consists of 51 students. The experimental group was subjected to the lessons arranged with the GeoGebra software in computer assisted teaching method, while the control group was subjected to the lessons shaped with constructivist instruction. The data collected after 5 weeks of application show that there is a meaningful difference between experimental and control groups’ achievement in trigonometry. This difference is in favor of the experimental group which had lessons with GeoGebra.