Question

How much fabric is required to cover x buttons in the shape of a circle whose radius is 3x ?

Answer 1

Radius of 1 button = r = 3x

Fabric required to cover 1 button = Area of the circle

=
`\pi r^(2)`

=
`\pi (3x)^(2)`

=
`9\pi x^(2)`

Total number of buttons = x

Fabric required to cover 1 button =
`9\pi x^(2)`

Fabric required to cover x buttons =
`x(9\pi x^(2) )`

`=9\pi x^(3)`

Hence, fabric required to cover x buttons
`=9\pi x^(3)` sq. units