The Effect of Using Powerpoint Media on The Ability to Solve Mathematical Problems of Flat Shapes. Riemann: Research of Mathematics and Mathematics Education, [S. l.], v. 6, n. 2, p. 223–233, 2024. DOI: 10.38114/6twbwb70. Disponível em: https://journal.sanagustin.ac.id/index.php/reimann/article/view/40.. Acesso em: 24 mar. 2026.