Question

the diameter of a roller is 84cm and it's length is 120cm. it takes 500 complete revolution to move once cover to level a playground. find the area of the playground is m square
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Answer 1

Radius of the roller (r) = 84/ 2 cm = 42 cm

Length of the roller (h) = 120 cm

Curved surface area of the roller = 2πrh = 2 × 22/ 7 × 42 × 120 cm2 = 44 × 720 cm2 = 31680 cm2

∴ area covered by the roller in 1 revolution = 31680 cm2

∴ area covered by the roller in 500 revolutions = 31680 × 500 cm2 = 15840000 cm

Hence, area of the playground = 15840000/ 100× 100 m2 = 1584 m2

Answer 2

Answer:

given

the diameter of roller=84cm

the radius of roller=84/2=42cm

the length of roller=120cm

so,

total surface area of roller=2πrh

=2*22/7*42*120

=2*22*6*120

=31680cm^2

give in the question

it takes 500 complete revolution to move once cover to level a playground

thus

Area of playground=31680*500

=15840000cm^2

hence :-

the area of playground is 15840000cm^2

or 1584m^2

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