<![CDATA[This research is motivated by the low geometry learning outcomes of seventh-grade students due to the use of conventional teaching strategies that are monotonous, abstract, and teacher-centered. The focus of this research is directed at improving students' mathematics learning outcomes through the implementation of the discovery learning model on spatial geometry. The type of research applied is Classroom Action Research (CAR), conducted collaboratively in two cycles at SMPK Wignya Mandala Tumpang. The operational procedures in each cycle are carried out systematically through the stages of action planning, discovery syntax implementation, classroom activity observation, and periodic reflection. Data collection techniques include participatory observation, documentation, and cognitive learning outcome tests in the form of multiple-choice and essay questions, which are analyzed descriptively qualitatively. The research findings indicate that the application of the discovery learning model with the aid of spatial teaching aids is effective in gradually boosting academic achievement. Quantitative data recorded an average pre-action score of only 45 with a classical completion percentage of 12.5 percent. This achievement jumped in cycle I to an average of 70 with a 50 percent completion rate, and peaked in cycle II with an average class score of 87.5 and a classical completion rate of 87.5 percent. The main conclusion confirms that this model successfully fosters cognitive independence and student learning motivation. ABSTRAK Penelitian ini dilatarbelakangi oleh rendahnya hasil belajar geometri siswa kelas VII akibat penggunaan strategi pengajaran konvensional yang monoton, abstrak, dan berpusat pada guru. Fokus masalah dalam riset ini diarahkan pada upaya peningkatan hasil belajar matematika siswa melalui pengimplementasian model pembelajaran discovery learning pada materi bangun ruang. Jenis penelitian yang diterapkan adalah Penelitian Tindakan Kelas (PTK) yang dilaksanakan secara kolaboratif dalam dua siklus di SMPK Wignya Mandala Tumpang. Prosedur operasional pada setiap siklus dijalankan secara sistematis melalui tahapan perencanaan tindakan, pelaksanaan sintaks penemuan, observasi aktivitas kelas, dan refleksi berkala. Teknik pengumpulan data ditempuh melalui observasi partisipatif, dokumentasi, serta tes hasil belajar kognitif berbentuk pilihan ganda dan esai yang dianalisis secara deskriptif kualitatif. Temuan penelitian menunjukkan bahwa penerapan model discovery learning berbantuan alat peraga ruang efektif mendongkrak capaian akademis secara bertahap. Data kuantitatif mencatat nilai rata-rata pra-tindakan hanya sebesar 45 dengan persentase ketuntasan klasikal 12,5 persen. Capaian ini melonjak pada siklus I menjadi rata-rata 70 dengan tingkat ketuntasan 50 persen, dan mencapai puncaknya pada siklus II dengan rata-rata nilai kelas 87,5 serta tingkat ketuntasan klasikal menyentuh 87,5 persen. Simpulan utama menegaskan bahwa model ini sukses menumbuhkan kemandirian kognitif dan motivasi belajar siswa. ]]>
