by Hyeseong Kang and Eunsung Jekal
Journal of Engineering Research and Sciences, Volume 05, Issue 05, Page # 12-18, 2026; DOI: 10.55708/js0505002
Abstract: This study aims to analyze the hierarchical development of the triangle concept across elementary and secondary mathematics curricula through the theoretical lens of Van Hiele’s geometric thinking levels. The triangle is introduced in elementary school as a visual and perceptual object, reinterpreted in middle school as a structure involving relationships among sides and angles, and… Read More

(This article belongs to the Section Education and Educational Research (EER))