Redefinition of the Kinds of Quadrilateral Based on the Angles and Sides

Abstract

Geometry is a branch in mathematics having important and strategic role to develop learners' spatial and higher order thinking skills. Both of them can be achieved by learner whenever the concepts of geometry are studied through inqury-discovery process. Therefore, redefinition of all kinds of convex qaudrilateral and their properties through analysis and investigation with respect to measure of its angles or sides. This study are done to have primely structure of convex quadrilateral that implies to acheive the objective of geometry learning. The method of study is initiated by reviewing and evaluating recent references discussing definition and property of quadrilateral, and then create what should be invented. Based on the study has been done, it was obtained many kinds of quadrilateral based on angles or/and sides and then their property that shows primely structure of convex quadrilateral concepts.