Understanding Quadrilaterals - NCERT Class 8 Maths
The chapter 3 begins with an introduction to polygons and classification of polygons. Convex and concave polygons, regular and irregular polygons are also described in detail here.The angle sum property which is one of the most useful results is explained in detail here. In the later part of the chapter, different kinds of quadrilaterals such trapezium, kite and parallelograms are described in detail. Then the elements, angles and diagonals of a parallelogram are discussed in the next section of the chapter.Some special parallelograms such as rhombus, rectangle, and square are explained in the last part of the section.