Mathematics Teachers' Understanding of the Concept of Radian

Trigonometry is among the mathematics subjects that students have difficulty in understanding due to the lack of proper understanding of the basic concepts. Research on radian, a concept that is among the fundamental concepts of trigonometry, has revealed that teachers, pre-service teachers and students lack, in some regards, proper conceptual knowledge about the subject term. Accordingly, studies on the issue bear particular importance. In the relevant literature, studies on the concept of radian focus mainly on students and pre-service teachers. However, there are not any national and contemporary studies that are conducted with teachers. In view of these, the current study aims to analyze mathematics teachers' ways of understanding of the concept of radian. In this regard, the study attempts to explore the reasons behind teachers' lack of conceptual knowledge regarding the concept of radian and to propose solutions that would help eliminate these reasons. The study employs case study method. The sample group consists of 41 in-service mathematics teachers who work in different types of schools. General Information Form and Concept Test developed by the researchers of the study as well as unstructured face-to-face interviews were utilized as data collection tools. As a consequence, majority of the participant teachers were found to lack an accurate and complete understanding of the concept of radian and to have some conceptual misunderstandings regarding the subject. In the conclusion section, findings of the study are discussed in relation to the relevant literature and some recommendations are made for teaching the concept of radian more efficiently.