Question

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

Answer 1

Diameter of roller = 84 cm
Circumference of roller =$\pi \times d=\frac{22}{7}\times 84=22\times 12=264cm$.
In 1 revolution, the distance covered is 264 cm.
Hence, in 500 revolutions the distance covered = $500\times 264=132000cm=1320m$.
Length of roller = 120 cm = 1.2 m.
Hence, the area of playground = distance $\times$ length of roller = $1320\times 1.2=1584sqm$.