An Analysis of Mathematical Errors and Misconceptions in Similar Triangles Problems Among Grade 9 Students at Suratthani School

Abstract

This study aims to analyze errors and misconceptions in solving mathematical problems related to similar triangles among Grade 9 students. The sample consisted of 45 Grade 9 students from Suratthani School, selected through purposive sampling due to their diverse approaches to problem-solving. Additionally, six students were randomly selected for qualitative interviews to gather in-depth insights. The research instruments included a test on mathematical problems related to similar triangles, designed as an open-ended assessment with five questions. Data were analyzed using both quantitative and qualitative methods. The findings revealed five major types of errors in students' test responses: 1. incorrect use of information (64.44%), 2. distortion of theorems, rules, formulas, definitions, or properties (35.56%), 3. misinterpretation of language (26.67%), 4. technical errors in problem-solving (20.00%), and 5. lack of verification during problem-solving (15.56%). Regarding misconceptions, the study identified four main types in descending order of prevalence: 1. misinterpretation (64.44%), 2. inadequate understanding of mathematical facts (53.33%), 3. limited conceptualization (40.00%), and 4. overgeneralization beyond the given scope or conditions (17.78%). The qualitative interviews with the target group corroborated the quantitative data, providing additional insights. These findings are valuable for teachers in designing instructional strategies tailored to diverse learning needs, including students with slower learning progress and those with high potential. The study contributes to developing effective learning approaches that address specific student groups.