Background/purpose: It is an urgent necessity to identify geometric conceptual errors among students at different levels. These errors cannot be ignored, as they hinder the learning of related concepts. Teachers need to be aware of these errors, which are often embedded in students' cognitive structures, so that they can work on eliminating them…

This qualitative case study, grounded within the interpretive paradigm, analyzed the errors and misconceptions made by 11th-grade learners when tackling the tangent-chord theorem task in Euclidean geometry. Studying Euclidean geometry helps learners develop critical thinking skills, such as constructing arguments and applying logical reasoning.…