The chapter deals with the angle sum property of a quadrilateral, classification of polygons, the concept of curves, the concept of polygons, different types of curves, exterior angles of a polygon and its property, and interior angles of a polygon.
In Maths chapter 15, Understanding Shapes – I(Polygons) covers the types of polygons as regular polygon, irregular polygon, convex polygon, concave polygon, simple polygon, and complex polygon. In addition, the concept of polygons includes side, vertex, adjacent sides, adjacent vertices, and diagonal along with opposite sides, angle, adjacent angle, and opposite angles. The types of curves include topics such as closed curves and simple curves. The chapter contains only one exercise, which has simple questions that lay the basis of geometry. Further in RD Sharma Maths chapter 15, Understanding Shapes – I(Polygons), the questions are based on various types of polygons. The chapter also teaches the students that not every closed curve is a polygon, but every polygon is a closed curve. The chapter also helps students demarcate between the regular and irregular polygons.
The chapter further elaborates on the naming of the polygons, and the diagonals of various polygons are also discussed. The chapter also includes questions where the students are needed to identify the type of curve. The students get to understand a very basic concept in geometry through this chapter, and these basic concepts prove very crucial in the chapters that follow.