Question

A road-roller is of diameter 80 centimetres and length 1.2 metres. What is the area of ground levelled, as it rolls once?

Answer 1

Diametre of the road roller = 80 cm = 0.8 m (1 m = 100 cm)

Radius (r) of the road roller =

Length of the road roller = 1.2 m

Perimeter of the circular base = 2πr

= (2 × 3.14 × 0.4) m

= 2.512 m

If the road roller rolls once, it covers area equal to its curved surface area.

Curved surface area of the road roller = Perimeter of the base × Length of the road roller

= (2.72 × 1.2) m²

= 3.014 m²

Thus, 3.014 m² area of the ground is levelled.