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प्रश्न
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 m2?
`["Assume "pi=22/7]`
उत्तर
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 = (84/2)cm = 42cm
CSA of roller = 2πrh
`=(2xx22/7xx42xx120)cm^2`
= 31680 cm2
Area of field = 500 × CSA of roller
= (500 × 31680) cm2
= 15840000 cm2
`=15840000/(100xx100) m^2`
= 1584 m2
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