<![CDATA[Understanding mathematical concepts, particularly plane geometry, remains a challenge for elementary school students due to the abstract nature of mathematics instruction and the limited integration of contextual learning. This study aimed to determine the effectiveness of a Problem Based Learning (PBL) model based on ikat weaving ethnomathematics assisted by Augmented Reality (AR) in improving fourth-grade students’ understanding of plane geometry concepts. The study employed a quantitative approach using a quasi-experimental design with a non-equivalent control group design. The participants consisted of 60 fourth-grade students at SDN Kertajaya Surabaya, divided into an experimental class and a control class. Data were collected through pretest and posttest instruments consisting of ten essay questions measuring students’ conceptual understanding of plane geometry. The data were analyzed using normality tests, homogeneity tests, Independent Samples t-test, and N-Gain analysis. The results showed that the experimental class achieved a higher posttest mean score (85.00) than the control class (75.66). The Independent Samples t-test revealed a significance value of 0.015 (p < 0.05), indicating a statistically significant difference between the two groups. Furthermore, the N-Gain score of the experimental class (0.6367) was higher than that of the control class (0.4518), both categorized as moderate improvement. These findings indicate that the PBL model based on ikat weaving ethnomathematics assisted by Augmented Reality is effective in enhancing elementary school students’ understanding of plane geometry concepts]]>
