Problems associated with learning to represent and define quadrilaterals

Geometric reasoning requires the skills of representing and defining quadrilaterals. In this paper, we are reporting on the results of an investigation into the ways students communicated their understanding of 2-dimensional geometric concepts using diagrams and keywords to describe quadrilaterals. The results showed that whenever Year 8 students used diagrams as part of their descriptions of shapes, mostly prototypical shapes were provided. Students also experienced difficulties discerning which properties could be used to define shapes. This paper provides insights into ways of analysing students' geometric reasoning