Efektivitas Model Project-Based Learning Terhadap Peningkatan Hasil Belajar Matematika Siswa Pada Materi Bangun Ruang Di Sekolah Dasar

This study aims to analyze the implementation of the Project-Based Learning (PjBL) model in improving students' mathematics learning outcomes in three-dimensional geometry at SD Swasta PKMI Telukdalam, Teluk Dalam District, South Nias Regency, Indonesia. This research employs a quantitative approach using a quasi-experimental method involving 15 elementary school students. Data are collected through tests, observations, and documentation. The research instruments consist of pretests and posttests designed to measure students' understanding of three-dimensional geometric concepts. The learning activities involve designing, constructing, and presenting geometric models using simple materials available in the surrounding environment. The collected data are analyzed using descriptive and inferential statistics, as well as the Normalized Gain (N-Gain) formula, to determine improvements in students' learning outcomes. The implementation of PjBL is expected to create a more active, creative, collaborative, and contextual mathematics learning environment. In addition to improving conceptual understanding, this learning model is expected to develop students' critical thinking, creativity, responsibility, and teamwork skills. This study is expected to contribute to the development of innovative, meaningful, and student-centered mathematics learning strategies in elementary education.