This study explored how GeoGebra-supported instruction influences Senior High School (SHS) students’ achievement in circle theorem. Using a quasi-experimental design, the study employed pre-test and post-test control groups to allow for a clear comparison of learning outcomes. The participants were eighty second-year SHS students drawn from two public senior high schools in the Okaikwei North District of the Greater Accra Region, selected through systematic random sampling. Students in the experimental group were taught circle theorem concepts using GeoGebra, which allowed them to visualize and manipulate geometric ideas dynamically, while those in the control group were taught using the traditional, teacher-centred approach. Data were gathered through a geometry achievement test and analyzed using descriptive statistics and independent samples t-tests at a 5% level of significance. The results showed no statistically significant difference between the two groups in the pre-test, suggesting that the students started at comparable levels. However, a significant difference emerged in the post-test, with students in the GeoGebra group outperforming their counterparts in the control group. These findings provide clear evidence that GeoGebra-supported instruction can meaningfully improve students’ understanding and achievement in circle theorem. Based on these outcomes, the study recommends that dynamic geometry software such as GeoGebra be deliberately integrated into SHS mathematics teaching to support deeper learning and improved performance.
Keywords: Achievement, GeoGebra, Geometry, circle theorem
