Curved-side spatial structures are one of the geometry materials taught at the junior high school/Islamic junior high school level, especially in class IX. Completing questions up to the room side arch can help students finish problems contextual to others. Training students' critical thinking skills in solving a mathematical problem is one of the tasks of a mathematics teacher. From the data from the researcher's interview with the mathematics teacher of grade IX students of Palu Christian Middle School, information was obtained that the teacher had carried out learning activities with various strategies to train students' critical thinking skills in solving mathematical problems. However, students' critical thinking skills did not change, and there was no increase. This study aims to obtain a clear description of the critical thinking skills of grade IX students in solving mathematical problems. This research is a qualitative study. The data collection methods used in this study were test and interview methods. The critical thinking indicators used were focus, reason, inference, situation, clarity, and overview. This study involved 28 Palu Christian Middle School students in the odd semester of the 2022/2023 Academic Year. Three students were selected as research subjects, where one student represented each level of mathematical ability, namely high mathematical ability (ST), medium mathematical ability (SS), and low mathematical ability (SR). The results of this study indicate that students with high mathematical ability meet all critical thinking indicators. Students with moderate mathematical abilities fulfill several indicators of critical thinking, namely focus, clarity, and overview. Students with low mathematical abilities fulfill several indicators of critical thinking, namely clarity and overview.
Majaga et al. (Thu,) studied this question.