Question

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

Answer 1

Heya,

Given:-
Diameter = 84cm = 0.84m
Length = 120cm = 1.2m

To find:-
Area of the playground.

Solution:-

Radius = 0.84/2 = 0.42m
Height = 1.2m

CSA of the playground = 2πrh
CSA of the playground = 2 × 22/7 × 0.42 × 1.2
CSA of the playground = 2 × 22 × 0.06 × 1.2
CSA of the playground = 44 × 0.072
CSA of the playground = 3.178m^2

Area = 500 × 3.178
Area = 1584m^2

Hope my answer helps you :)

Regards,
Shobana

Answer 2

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Length of the roller (h) = 120 cm = 1.2 m

Radius of the cylinder = 84/2 cm = 42 cm = 0.42 m

Total no. of revolutions = 500

Distance covered by roller in one revolution = Curved surface area = 2πrh

= (2 × 22/7 × 0.42 × 1.2) m2 = 3.168 m2

Area of the playground = (500 × 3.168) m2 = 1584 m2 .