Question

A cylindrical pillar is 100 cm in diameter and 2.5m In height. Find the cost of painting curved surface of the pillar at the rate of 16 per m ^ 2 .​

Answer 1

Given :-

• Diameter = 100 cm
• Height = 2.5 m
• Rate = Rs. 16 per m²

To Find :-

Cost of painting it's CSA

Solution :-

We know that

1 m = 100 cm

So, the diameter of pillar is 1 m

Now

Radius = Diameter/2

⇒ Radius = 1/2

⇒ Radius = 0.5 m

Now

CSA of cylinder = 2πrh

⇒ CSA = 2 × π × 0.5 × 2.5

⇒ CSA = 2.5π m²

Now

Cost = Rate × CSA

⇒ Cost = 16 × 2.5π

⇒ Cost = 40π

⇒ Cost = 40 × 3.14

⇒ Cost = Rs. 125.6

Hence,

Cost of painting it's CSA is Rs. 125.6

Answer 2

I HAVE ATTACHED THE HALF OF THE EXPLANATION IN THE IMAGE

⇒Cost of painting 1 m²

AREA = Rs.12.50

⇒Cost of painting 5.5 m²

AREA = Rs.5.5×12.50

= Rs.68.75

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