The purpose of this study was to analyze the activities in the Problem-Based Learning (PBL) methodology among high school students when solving problems related to the field of plane figures, both in extra-mathematical and intra-mathematical environments. The research was qualitative and constituted a case study. The technique used to select the research subjects was intentional sampling, which involved the selection of a group of sixth-grade students. The data were collected through tests and interviews. The data analysis techniques employed included data reduction, data presentation, and drawing conclusions. The results showed that the students used perimeter calculation as an erroneous representation of area calculation, and they exhibited a lack of argumentation during problem-solving. Furthermore, they expressed a lack of recognition of certain plane figures and their properties, a characteristic of students at the visualization level, also known as the first level of the Van Hiele levels. Another significant finding in this study was the use of problems involving extra-mathematical contexts, which had a greater impact on the problem-solving process and the understanding of mathematical concepts.