Question

The inner diameter of a circular well is 3.5m. It is 10m deep. Find

(i) its inner curved surface area,

(ii) the cost of plastering this curved surface at the rate of Rs. 40 per m2.

(Assume π = 22/7)​

Answer 1

CSA=2πrh

put the value of r , h and π then u will get your answer

I hope it will help u

#stay_safe

Answer 2

Given:-

• d = 3.5 m
• r = 3.5/2 × 10 m = 7/4 m
• h = 10 m

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To find:-

• Inner curved surface area
• Cost of plastering this curved surface at the rate of Rs. 40 per m².

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Solution:-

★ Using Formula

$\boxed{ \red{ \sf \: Curved \: surface \: area =2πrh}}$

$\sf \longrightarrow 2 \times \frac{22}{7} \times \frac{7}{4} \times 10$

$\sf \longrightarrow 110 \: {cm}^{2}$

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★ Rate

$\sf \longrightarrow ₹ \: 40 \times 110$

$\sf \longrightarrow ₹ \: 4400$

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Therefore, the cost of plastering the curved surface of the well is Rs. 4400.