The diameter of a roller is 72 cm and its length is 120 cm. It takes 200 complete revolutions to move over to level playground. Find the area of the playground.


Diameter of the roller$=72\ cm$

Length of the roller$=120\ cm$.
Number of revolutions taken to level the playground$=200$.
To do:

We have to find the area of the playground.


Radius of the roller$=\frac{72}{2}\ cm=36\ cm$.

We know that,

Curved surface area of a cylinder of radius r and height h is $2 \pi rh$.


Area covered in 1 revolution$=$Curved surface area of the roller

Area of the playground$=$Number of revolutions$\times$Curved surface area of the roller

$=200\times2\times3.14\times36\times120\ cm^2$

$=5425920\ cm^2$

$=\frac{5425920}{10000}\ m^2$

$=542.592\ m^2$

The area of the playground is $542.592\ m^2$.


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