Question

From a circular sheet of radius $4cm$, a circle of radius $3cm$ is removed. Find the area of the remaining sheet. (Take $\pi =3.14$)

Answer 1

Area of the remaining part$=$Area of bigger circle$-$Area of the smaller circle.

Consider the bigger circle: Radius $r=4cm$

Area$=\pi r^2=3.14\times 4^2=\frac{314}{100}\times 16=\frac{5024}{100}=50.24{cm}^2$

Consider the smaller circle: Radius $r=3cm$

Area$=\pi r^2=3.14\times 3^2=\frac{314}{100}\times 9=\frac{2826}{100}=28.26{cm}^2$

Area of the remaining part$=$Area of bigger circle$-$Area of the smaller circle.

$=50.24{cm}^2-28.26{cm}^2=21.98{cm}^2$

$\therefore$ Area of remaining sheet is $21.98{cm}^2$