* Quadrilateral is also tetragon, quadrangle [http://www.mathopenref.com/quadrilateral.html click here]
* Quadrilateral is also tetragon, quadrangle [http://www.mathopenref.com/quadrilateral.html click here]
* http://www.slideshare.net/muzzu1999/types-of-quadrilaterals-and-its-properties-group-4 : This website has a very good avtivity on properties of quadrilaterals.
* http://www.slideshare.net/muzzu1999/types-of-quadrilaterals-and-its-properties-group-4 : This website has a very good avtivity on properties of quadrilaterals.
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* http://www.cimt.plymouth.ac.uk/projects/mepres/book8/bk8i1/bk8_1i3.htm This is a very good website for students to understand classification of quadrilaterals as per their properties. The activity is given in the form of a flow chart.