The study utilized mixed method approach involving one group pretest-posttest pre-experimental design to explore the effect of using GeoGebra on 80 second year Senoir High school students’ effectiveness of the use of GeoGebra on their van Hiele level of geometric thinking. Inferential statistics of one-way ANOVA and paired sample T-test were used to test the hypotheses. Findings revealed that the use of GeoGebra on students van Hiele level of geometric thinking was effective because majority of the students obtained more than half of the marks allotted to the test. The hypotheses concluded that there was a statistically significant difference in students van Hiele geometric thinking levels (VHGTL) after GeoGebra instruction and also in their pre-VHGTL and post-VHGTL scores. Heads of senior high schools and other educational stakeholders’ should organise in- service training for mathematics teachers to equip them with the required skills on how to utilise GeoGebra for effective teaching and learning of geometry and other lessons in mathematics.
Keywords: GeoGebra, Geometry, Senior High Students, Van Hiele geometric thinking level.
