Yosafat Ardian Kristiarta, Wahyu Setyaningrum and Marsigit 2023. Problem Solving Approach Based on Blended Learning on Trigonometric Comparison of Right Triangles on Mathematical Concept Understanding Ability. Journal for Lesson and Learning Studies. 6, 3 (Dec. 2023), 516–526. DOI:https://doi.org/10.23887/jlls.v6i3.67275.