Analysing the misconceptions that students have about polygon and special quadrilaterals

The aim of this study is to examine 7th grade students' misconceptions that they did on the topics of polygons and special quadrilaterals. The data was collected and analysed by using mix method design in which elements of qualitative and quantitative research approaches are combined in a single study. The study was conducted in 5 different schools of Gaziantep and the data consists of 229 students (124 girls, 105 boys) who are in the 7th grade and 8 Mathematics teachers. In the quantitative method part, the data was collected by using diagnostic test which was formed by examining the related literature. Questionnaire of the diagnostic test were prepared by considering the acquisitions (sub problems). Teachers were asked their opinion about the questions as well. In the quantitative part, descriptive statistics, T test and one-way ANOVA test were applied by using the SPSS 17.0 (Statistical Package for the Social Science) package software. In addition, in order to determine error types and misconceptions, descriptive analysis was applied by making use of the related literature. In the qualitative part, in order to examine the teachers' beliefs, a content analysis technique was applied by creating codes, sub-codes and themes. The results indicate that the students have some misconceptions about polygons and special quadrilaterals. Qualitative data provides the reasons of students' misconceptions and the suggestions to eliminate them. Consequently, it is suggested that in order to eliminate the students' misconceptions different methods and techniques should be used in addition to giving examples except from the prototype shapes and doing a lesson with hierarchical teaching method. Keywords: Special quadrilaterals, polygons, misconceptions, geometry