Nanang Hadi Hariyanto, Purwanto, Vita Kusumasari
Junior high school students are expected to reach Van Hiele’s level 2 (informal deduction) in geometry, but many struggle due to recurring errors. This study examines how these errors are influenced by students' Florence Littauer personality types. Using a descriptive qualitative approach, 42 ninth-grade students from a public junior high school in Malang were assessed on similarity and congruence of triangles. Eight students were selected based on personality assessments and problem-solving performance. Data collection involved written tests, think-aloud protocols, and interviews, with errors categorized according to Van Hiele’s levels of thinking. Results show that sanguine, melancholic, and phlegmatic students remain at the visualization level. Sanguine students, prone to distraction, made reading, comprehension, and transformation errors. Melancholic students, though detail-oriented, struggled with reading and transformation errors, while phlegmatic students’ pessimism led to transformation errors and incomplete solutions. Choleric students reached the analysis level but failed to progress to informal deduction due to their tendency to prioritize practical solutions, resulting in reading, transformation, and process skills errors. This study contributes to understanding personality-based error patterns in geometry, emphasizing the need for tailored instructional strategies to help students advance through Van Hiele’s levels of thinking. © 2025 American Institute of Physics Inc.. All rights reserved.
Department of Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Malang, Indonesia
