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the diameter of a 120 cm long roller is 84 cm It takes 1000 complete revolutions in moving once over to level a playground what is the area of the playground |
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Answer» Answer: Radius of the ROLLER = diameter ÷ 2 = 84 ÷ 2 = 42 cm
Length of the roller = 120 cm
Curved SURFACE Area of the Roller (Cylindrical shape) = begin mathsize 16px style 2 πrh SPACE space equals space 2 space cross times 22 over 7 cross times 42 space cross times space 120 space equals space 31680 space cm squared end style Therefore the area covered by the roller in ONE revolution = 31680 cm2 Therefore the area covered by the roller in 1000 REVOLUTIONS = 31680 × 1000 = 31680000 cm2
Therefore the area of the play ground = 31680000 cm2 = 3168 m2
→ l × b = 3168 → l × 32 = 3168 → l = 99 m |
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