Q. 44.4( 300 Votes )

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

Answer :

It can be observed that a roller is cylindrical

Height (h) of cylindrical roller = Length of roller

= 120 cm

Radius (r) of the circular end of roller = = 42 cm

Curved Surface Area (CSA) of roller = 2πrh

= 2 * * 42 * 120 cm^{2}

= 31680 cm^{2}

Area of field = 500 × CSA of roller

= (500 × 31680) cm^{2}

= 15840000 cm^{2}

= 1584 m^{2 }(∵ 1 m^{2} = 10000 cm^{2})

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