Question

the diameter of aroller is 84cm and its length is 120cm it takes 500 complete revolution to move once over to level a playground. find the area of the playground

Answer 1

Hey !!!!

This is your answer.......

Given :

Diameter of roller = 84 cm.
So, radius = d/2 = 42 cm.

Length of roller = 120 cm.

As the roller is in shape of cylinder. So, we will use CSA of cylinder formula to find the CSA of roller.

CSA of Cylinder = 2πrh
= 2 × 22/7 × 42 × 120
= 44 × 6 × 120
= 264 × 120
= 31680 cm².

Hence, the curved surface area of roller is 31680 cm².

It is given that it takes 500 revolutions.
So, total area covered by it so be
CSA of roller × 500
= 31680 ×500
= 15840000 cm².

We know that 10000 cm² = 1 m².

So, 15840000 cm² = 1584 m².

Hence, the area of playground is 15840000 cm² or 1584 m².

Hope it helps

Answer 2

Heya,

Diameter = 84cm = 0.84m
Length = 120cm = 1.2m
Radius = 84/2 = 42cm = 0.42m
Revolution = 500

CSA of the roller = 2πrh
CSA of the roller = 2 × 22/7 × 0.42 × 1.2
CSA of the roller = 2 × 22 × 0.06 × 1.2
CSA of the roller = 44 × 0.072
CSA of the roller = 3.168m^2

Area of the playground = CSA × 500
Area of the playground = 3.168 × 500
Area of the playground = 1584m^2

Hope my answer helps you :)

Regards,
Shobana