This study analyses the students’ performances in two-dimensional
transformation geometry and explores the mistakes made by the students
taking the analytic geometry course given by researchers. An examination
was given to students of Education Faculties who have taken the analytic
geometry course at Eskisehir Osmangazi University in Turkey. The subject
of this study included 126 third-year students in the Department of
Mathematics Education. Data were collected from a seven questions exam.
This exam consisted of three procedural questions, two conceptual
questions and two procedural–conceptual questions. In data analysis, a
descriptor code key was used. When the students’ overall performances
were considered for all seven questions, the results showed that they did not
understand how to apply rotation transformation. The mostly observed
mistakes showed that the students seemed to know the algebraic meaning
of translation and also rotation but they did not seem to understand the
geometric meaning of them.