Abstract: In Rwamagana District, Rwanda, students’ performance in trigonometry is extremely poor, this is to a great extent attributed to the use of conventional teaching methods. The purpose of this study is to ascertain that Microsoft Excel is used as a learning tool to enhance students’ understanding of the concept of trigonometry. The target population was all senior five students enrolled in mathematics related combinations from 32 schools of Rwamagana District, Rwanda. The study used a quasi-experimental design in which 32 students from two schools were selected purposively as a control group and 37 students from two schools were selected purposively as experimental group. The results showed that students who received instruction using Microsoft Excel performed noticeably better than those who received instruction using traditional methods. The post-test mean score for the experimental group was 31.23 (SD = 3.42), significantly higher than the control group’s score of 24.78 (SD = 5.15). This difference was statistically significant (p = 0.000). Students who used Excel also performed more consistently and showed a deeper conceptual grasp of trigonometric functions. According to the study’s findings, incorporating Microsoft Excel into trigonometry lessons improves students’ academic performance. The study recommends mathematics teachers to use Excel as a regular teaching tool and support blended learning strategies.

Abstract: This study sought out to investigate level three students’ misconceptions affecting performance in trigonometry in two selected schools of Kicukiro District. The target population was 386 level three students in selected TVET schools located in Kicukiro District for 2021-2022 academic year. Among these schools, one public and one private school were chosen purposively and a sample of 196 participants was taken using stratified sampling methods so that each trade in the selected schools was represented. This study followed a descriptive survey research design and the data from selected participants were collected using questionnaires and analysed using SPSS. The results indicated that 70% of the students have positive attitudes towards trigonometry and they were interested in this unit, but trigonometric concepts were not explained clearly and they were not familiar with notations. They also have misconceptions in making invalid references and conceptual misunderstanding on trigonometric ratios, trigonometric equations and solving word problems. The study recommends trainers to motivate their trainees in learning trigonometry, to explain trigonometric concepts clearly; provide more exercises, including word problems, and advise trainees to avoid carelessness while doing assignments.