Question

A diameter of a roller is 0.84m and its length is 1.2m, It takes 200 complete revolutions to move once over to level a playground. Find the area of the playground in m².​ jo answer dega 80 points dunga

Answer 1

Required Answer:-

Imagine the situation given here...

The roller is in the shape of a cylinder and it is rolling in a playground. The total area of the playground will be the total curved surface area of the cylinder × no. of revolutions taken.

GiveN:-

• Diameter of roller = 0.84 m (r = 0.42 m)
• Length of roller = 1.2 m
• No. of complete revolutions = 200

To FinD:-

• Total area of the playground$?$

Solution:-

In 1 revolution, it will cover the part of area of playground = curved surface area of the roller. And the CSA of cylinder is given by 2πrh

Plugging the values,

= 2πrh

= 2 × 22/7 × 42/100 × 12/10 m²

= 3.168 m²

Total area covered:

= Area covered in 1 revolution × No. of revolutions

= 3.168 m² × 200

= 633.60 m²

Hence:-

• Total area of the playground covered by the roller is given by 633.60 m²

Answer 2

Answer:

Given :-

Diameter = 0.84 m

Length = 1.2 m

Revolution = 200

To Find :-

Area

Solution :-

Radius = Diameter/2

Radius = 0.84/2

Radius = 0.42 m

Now

We will find its CSA

CSA = 2πrh

CSA = 2 × 22/7 × 0.42 × 1.2

CSA = 44/7 × 0.504

CSA = 22.176/7

CSA = 3.168 m²

Area covered = 200 × 3.168

Area covered = 633.6 m²