CBSE Class 9 Answered
The diameter of a roller 1 m long is 56 cm. If it takes 200 revolutions to level a playground, find the cost of levelling the playground at the rate of 50 paisa per m2.
Given: Diameter = 56 cm ⇒ radius (r) = 28 cm
Length (h) = 1 m = 100 cm
Let S be the curved surface area of the roller.
Area covered in 200 revolutions = 200×17600 cm2 = 3520000 cm2 = 352 m2