Sabaniatun, S., B. R. A. Febrilia, and E. Juliangkary. “The Problem Solving Ability of Students on the Material Perimeter and Area of a Triangle”. Edumatica : Jurnal Pendidikan Matematika, vol. 9, no. 2, Nov. 2019, pp. 1-13, doi:10.22437/edumatica.v9i02.6074.