Development and Validation of a Triangle Trigonometry E-Module

This study validated and evaluated the effectiveness of a developed Triangle Trigonometry E-Module on the mathematical performance of forty Grade 9 students at the University of Northern Philippines-Laboratory High School during the 2020-2021 academic year. The research employed a one-group pretest-posttest design, utilizing a 30-item validated test to assess student performance. Validation by experts rated the E-Module "highly valid" across content objectives, clarity, relevance, design, suitability, and testing. Results revealed a significant improvement in students' mathematical performance, with pretest scores rated "Poor" and posttest scores rated "Very Satisfactory." This demonstrates the E-Module's effectiveness in enhancing students’ understanding of trigonometric concepts. The study highlights the potential of e-modules as effective educational tools, especially in remote or blended learning contexts. Recommendations include adopting the Triangle Trigonometry E-Module across similar curricula, integrating e-modules in other subjects, and conducting remedial sessions for low-performing students. Future research is encouraged to validate these findings across different educational settings and subjects