Jais, E. et al. 2023. Hypothesis Design of Learning Trajectory Volume Building Flat Sided Spaces in Junior High Schools: Based on Van Hiele’s Theory. Jurnal Penelitian Pendidikan IPA. 9, 4 (Apr. 2023), 1778–1785. DOI:https://doi.org/10.29303/jppipa.v9i4.2722.