<![CDATA[The primary issue underlying this research is the low level of students' conceptual understanding of trigonometric ratios. This study focuses on developing instructional video media that are valid, practical, and effective as supporting instruments to optimize students' conceptual understanding of trigonometric ratios. The development followed the ADDIE (Analysis, Design, Development, Implementation, Evaluation) model and was tested on 23 tenth-grade students at SMA Negeri 4 Merauke. The research instruments consisted of expert validation sheets to measure the validity of the instructional videos, student response questionnaires to measure practicality, and test questions to measure effectiveness. Effectiveness was evaluated using a one-group pretest-posttest research design. The results indicated that the developed instructional videos are valid, with an Aiken’s Index ranging from 0.77 to 0.82, covering aspects of display, content, utility, material, presentation, and language. The media also met the practicality criteria, with student response percentages across all aspects ranging from 79.29% to 81.43%. Regarding effectiveness, an N-Gain score of 0.802 was obtained, falling into the "high" category. These findings demonstrate that the developed instructional videos are feasible for use as an alternative medium to enhance students' conceptual understanding of trigonometric ratios.an perbandingan trigonometri.Keyword: Conceptual understanding, Learning video development, Trigonometric ratios ]]>
