Science and Education Publishing American Journal of Educational Research 2327-6150 4 16 2016 10 20 Applying the APOS Theory to Study the Student Understanding of Polar Coordinates 1149 1156 EN Vahid Borji Michael. Gr. Voskoglou Mathematical Sciences, School of Technological Applications, Graduate Technological Educational Institute of Western Greece, Patras, Greece EDUCATION20164165 10.12691/education-4-16-5 2016 5 5 2016 8 22 2016 10 18 A Genetic Decomposition (GD) is developed in this paper, in terms of the APOS instructional treatment of mathematics, for teaching and learning the polar coordinates. The design of the GD is based on the conclusions obtained by a written test and by oral interviews performed on a group of students of the Physics Department of the University of Neyshabur, Iran.