The diameter of a roller is 84 cm and its length is 120 cm. It takes 500 complete revolutions to move once over to level a playground. Find the area of the playground in `m^2`.

Explanation

Here, length h = 84 cm
Diameter 2r = 120 cm
`rArr r = 60 cm`
Area of the ground covered in one rotation = curved surface area
`= 2pi rh`
`=2xx(22)/(7)xx60xx84`
`=31680 cm^(2)`
`therefore` Area of ground covered in 500 rotations `= 500xx31680 cm^(2)`
`=(500xx31680)/(100xx100)m^(2)=1584 m^(2)`
`therefore` Area of playground `= 1584 m^(2)`