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 the road roller is 84 cm and its length is 1 m.

Answer 1

Diameter = 84 cm
i.e., radius = 42 cm
Length = 1 m = 100 cm
Now, lateral surface area $=2\mathrm{\pi rh}=2\times \frac{22}{7}\times 42\times 100=26400{\mathrm{cm}}^2$
∴ Area of the road $=\mathrm{lateral}\mathrm{surface}\mathrm{area}\times \mathrm{no}.\mathrm{of}\mathrm{rotations}=26400\times 750=19800000{\mathrm{cm}}^2=1980{\mathrm{m}}^2$