Ethnomathematics didactic design to overcome students' learning barriers: similarity and congruence materials

Constraints in studying geometry often arise in the concept of congruence and similarity. The type of problem is that students do not understand the different concepts of congruence and congruence in two-dimensional fields. Students often cannot distinguish that two congruent flat shapes are not necessarily congruent and two congruent flat shapes are not always congruent. This study aims to design tactics on congruence and harmony. The research method used was mixed. In particular, this study includes designing, following three stages of Didactical Design Research (DDR), namely the didactic situation analysis before learning (prospective analysis), methadactic analysis, and retrospective analysis. Furthermore, based on learning designed mathematics learning with an ethnomathematics approach.