Page 1 UNDERSTANDING QUADRILATERALS 37 3.1 Introduction Y ou know that the paper is a model for a plane surface. When you join a number of points without lifting a pencil from the paper (and without retracing any portion of the drawing other than single points), you get a plane curve. Try to recall different varieties of curves you have seen in the earlier classes. Match the following: (Caution! A figure may match to more than one type). Figure Type (1) (a) Simple closed curve (2) (b) A closed curve that is not simple (3) (c) Simple curve that is not closed (4) (d) Not a simple curve Compare your matchings with those of your friends. Do they agree? 3.2 Polygons A simple closed curve made up of only line segments is called a polygon. Curves that are polygons Curves that are not polygons Understanding Quadrilaterals CHAPTER 3Read More

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