Direction: A hollow cylindrical tank whose bottom is closed and top is open is painted from outside as well as inside. The inner radius of the cylinder is 7 cm, and its thickness is 2 cm. The height of the cylinder is 21 cm.

Using the data given in the previous question, find the difference (in $s q c m$ ) between the curved surface area of the cylinder and the area of the cavity formed inside.

250 π

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325 π

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358 π

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368 π

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Solution

The correct option is C $358 π$
Radius of the conical cavity $= 4 c m$
Height of the conical cavity $= 3 c m$
So, its slant height $= 5 c m$
Difference $= 2 π \times 9 \times 21 - π \times 4 \times 5 = 378 π - 20 π = 358 π$
Hence, option $C$ is the correct answer.

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Similar questions

Q. Direction: A hollow cylindrical tank whose bottom is closed and top is open is painted from outside as well as inside. The inner radius of the cylinder is

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Find the approximate area (in

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Direction: A hollow cylindrical tank whose bottom is closed and top is open is painted from outside as well as inside. The inner radius of the cylinder is 7 cm, and its thickness is 2 cm. The height of the cylinder is 21 cm.

If another identical cylinder is placed over it, such that both the cylinders overlap each other, and their open ends combine together to form a new solid cylinder. Find the total surface area (in

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The correct option is C 358πRadius of the conical cavity =4 cm Height of the conical cavity =3 cm So, its slant height =5 cm Difference =2π × 9 × 21−π × 4 × 5=378π −20π =358π Hence, option C is the correct answer.

The correct option is C $358 π$
Radius of the conical cavity $= 4 c m$
Height of the conical cavity $= 3 c m$
So, its slant height $= 5 c m$
Difference $= 2 π \times 9 \times 21 - π \times 4 \times 5 = 378 π - 20 π = 358 π$
Hence, option $C$ is the correct answer.