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A metal pipe is 77 cm long. Inner diameter of cross section is 4 cm and outer diameter is 4.4 cm. Its inner curved surface area is:
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Explanation:
The inner curved surface area (CSA) of a cylindrical pipe is given by the formula:
CSA = 2πrh,
where:
– r is the inner radius of the circular base,
– h is the height (or length) of the cylinder.
From the problem:
– The length (h) of the pipe is 77 cm,
– The inner diameter of the cross-section is 4 cm, so the inner radius (r) is:
r = Diameter / 2 = 4 / 2 = 2 cm.
Substitute the values of r = 2 cm and h = 77 cm into the formula:
CSA = 2πrh.
Using π ≈ 22/7 for calculation:
CSA = 2 × (22/7) × 2 × 77.
Simplify step by step:
CSA = 2 × (22/7) × 154,
CSA = 2 × 22 × 22,
CSA = 968 cm².
Thus, the inner curved surface area of the metal pipe is 968 cm², which corresponds to option b) 968 cm².
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