Question

A playground has to be leveled out. A Roller of diameter 80cm and length 120cm makes 750 Revolution to level ground. find the area of a ground ​

Answer 1

✬ Area = 2262.825 m² ✬

Step-by-step explanation:

Given:

• Diameter of roller is 80 cm.
• Height of roller is 120 cm.
• Revolutions made by roller is 750.

To Find:

• What is the area of ground ?

Solution: Roller is in form of cylinder. Therefore,

➟ Diameter = 2(Radius)

➟ Radius = Diameter/2

➟ R = 80/2 = 40 cm.

Area covered by the roller in making one revolution will be the Curved surface area of Cylinder.

As we know that

★ CSA = 2πrh ★

• Taking π = 22/7

$\implies{\rm }$ 2(22/7)(40)120)

$\implies{\rm }$ 44/7(4800)

$\implies{\rm }$ 211200/7

$\implies{\rm }$ 30171 cm² (approx)

So, roller will cover the area of 30171 cm² in one revolution.

∴ Area covered in 750 revolutions = 750(Area covered in one revolution)

➯ Total area = 750(30171)

➯ Total area = 22628250 cm²

Changing in m².

• 1 m² = 10000 cm

∴ 22628250 cm² = 22628250/10000 = 2262.825 m²

Hence, area is 2262.825 m².

Answer 2

23 /45

36/6446

== 56/86

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