Development of an Interactive Ethnomathematics-Based E-LKPD on Magetan Local Architecture to Improve Understanding of Solid Geometry Concepts

Learning flat-sided solid geometry requires students to connect abstract mathematical concepts with visual representations and real-world objects. However, mathematics instruction at the junior high school level may still rely on conventional teaching methods, printed learning materials, and limited integration of local cultural contexts. This study aimed to develop and evaluate the validity, practicality, and effectiveness of an interactive mathematics electronic student worksheet (E-LKPD) based on the ethnomathematics of Magetan’s local architecture. The study employed a Research and Development (R&D) approach using the ADDIE model. The participants were eighth-grade students at SMP Negeri 1 Kawedanan, selected through purposive sampling, comprising 10 students from Class VIII-B for the limited trial and 27 students from Class VIII-A for the field trial. Effectiveness was evaluated using a one-group pretest–posttest design without a control group. Data were collected through interviews, observations, questionnaires, and learning outcome tests and analyzed using descriptive statistics, the paired-samples t-test, the Wilcoxon signed-rank test, and N-Gain analysis. The E-LKPD achieved an overall validity score of 89.6% and practicality scores of 88.4% in the limited trial and 85.7% in the field trial. Mean scores increased from 77 to 88 in the limited trial and from 83.52 to 90.74 in the field trial. Both statistical tests indicated significant pretest–posttest differences (p<.001). The N-Gain values were 0.533 and 0.421, respectively, both in the moderate category, while classical mastery reached 90% and 100%. These findings indicate that the E-LKPD meets the study’s criteria for validity, practicality, and effectiveness as an alternative learning resource for flat-sided solid geometry. Nevertheless, the absence of a control group limits conclusions about whether the observed improvements were attributable solely to the E-LKPD.