<![CDATA[Spatial reasoning is an essential ability in learning geometry, particularly in three-dimensional geometry. This ability encompasses visualization, mental rotation, and spatial orientation, which are required to solve three-dimensional geometric problems. Students' spatial reasoning strategies may differ due to the influence of their personality types. Therefore, this study aims to describe the spatial reasoning of eleventh-grade students at MAN 3 Kediri in solving three-dimensional geometry problems based on their personality types. This study employed a qualitative approach with a phenomenological design. The participants were selected purposively based on Carl Gustav Jung's personality type questionnaire and consisted of three extroverted students and three introverted students. Data were collected through written tests and interviews, then analyzed using the Miles and Huberman model. Technique triangulation was employed to ensure the trustworthiness of the data. The findings revealed that extroverted students were more proficient in collaborating, engaging in discussions, and utilizing visual aids to understand geometric transformations. However, they tended to be less accurate in calculations and less systematic in organizing their solution procedures. In contrast, introverted students tended to be more persistent, conducted in-depth independent analyses, and demonstrated well-structured problem-solving strategies. Nevertheless, they experienced difficulties in visualizing three-dimensional objects without the support of concrete illustrations. These findings indicate that personality type influences how students engage in spatial reasoning. Therefore, teachers are expected to adapt their instructional strategies, such as implementing interactive visual discussions for extroverted students and providing independent practice based on visual representations for introverted students, so that both groups can optimize their spatial reasoning abilities in mathematics learning.]]>
