On a square handkerchief, nine circular designs each of radius 7 cm are made (see Fig. 12.29). Find the area of the remaining portion of the handkerchief.
Number of circular design = 9
Radius of the circular design = 7 cm
There are three circles in one side of square handkerchief.
∴ Side of the square =3×diameter of circle=3×14=42 cm
Area of the square =42×42 cm2=1764 cm2
Area of the circle =πr2=227×7×7=154 cm2
Total area of the design =9×154=1386 cm2
Area of the remaining portion of the handkerchief = Area of the square - Total area of the design