Mathematical Reasoning Ability of Grades IX Students in Triangle Congruence Proof Learning Using Two-Column Proofs Strategy

Abstract

This study aims to describe the mathematical reasoning ability of grades IX students on the congruence triangle material after taking proof learning using the two-column proofs strategy. The subjects of this study were 25 students of class IX.2 SMP Negeri 1 Palembang. At the first and second meetings, students were taught how to prove the congruence of triangles using the two-column proofs strategy. The data was obtained from a written test consisting of 3 essay questions that have been adjusted to indicators of mathematical reasoning ability. The results showed that the students' mathematical reasoning ability was in the fair category with an average score of 64.33. Students are categorized as fair because some students have met the four reasoning indicators. Students also understand that in compiling evidence, first identify the existing facts, then develop arguments based on these facts using valid reasons. Then, when giving arguments to show evidence, students experience conceptual and principal problems so that they fail to provide valid arguments.