We know that parallelogram is also a quadrilateral. Let us also split such a quadrilateral into two triangles, find their areas and hence that of the parllelogram. Does this agree with the formula that you know already?
(a) Â Â We draw perpendiculars from opposite vertices on FI, i.e.Â
     Area of the polygon EFGHI
     =
     =  Â
     Â
(b) NQ is a diagonal. DrawÂ
       Â
∴  Area of polygon OPQRMN =Â
                        =Â
                        Â
                         Â
               Â
     Â
Polygon ABCDE is divided into parts as shown below. Find its area of AD = 8 cm, AH = 6 cm, AG = 4 cm, AF = 3 cm and perpendiculars BF = 2 cm, CH = 3 cm, EG = 2.5 cm.
 Area of polygon ABCDE = Area of  + .........
Area of  =Â
Area of trapezium FBCH = Â
                    =Â
Area of Â
Area ofÂ
So, the area of polygon ABCDE = ........
Find the area of polygon MNOPQR if MP = 9 cm, MD = 7 cm, MC = 6 cm, MB = 4 cm, MA = 2cm. NA, QC, QD and RB are perpendiculars to diagonal MP.
The shape of the top surface of a table is a trapezium. Find its area if its parallel sides are 1 m and 1.2 m and perpendicular distance between them is 0.8 m.