Question

A road roller takes 750 complete revolutions to move once over to level a road. Find the area of the road if the diameter of a road roller is 84 cm and length 1 m.

Answer 1

Given:
Diameter of road roller = 84 cm
Radius of road roller $r=\frac{d}{2}=\frac{84}{2}=42cm$
Length of road roller h = 1 m = 100 cm

Curved surface area of road roller = $2\pi rh=2\times \frac{22}{7}\times 42\times 100=26,400c{m}^2$
Area covered by road roller in 750 revolutions
= $26,400\times 750$
= $1,98,00,000c{m}^2$
= $1,980m^2[\because 1m^2=10,000c{m}^2]$
Hence, the area of the road is $1,980m^2$