Write out the formula of the polygon below
Polygon = Rectangle
Formula = Area of the rectangle = Length x Breadth
Length = 20ft , breadth = 9ft
Offset length = 20 - 18 = 2ft
Offset breadth = 9 - 6 = 3ft
Therefore Area of the rectangle = 20 x 9 - (3 x 2) ft² OR (9 x 18) +( 6 x 2) ft²
Hence the expression for the area of the polygon = 20 x 9 - (3 x 2) ft² OR (9 x 18) +( 6 x 2) ft²