The sum of the radius of the base and the height of a cylinder is 55 cm. If the height of the cylinder mentioned above is 15 cm more than the radius of its base, then what is the curved surface area of this cylinder? [Use ]
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Correct answer: D
Explanation
The correct answer is option 4 i.e. 4400 cm2.
The sum of the radius of the base and the height of a cylinder is 55 cm
The height of the cylinder mentioned above is 15 cm more than the radius of its base
Curved surface area of the cylinder = 2πrh ---- (1)
Where, r = radius and h = height
According to the question;
r + h = 55 ---- (2)
h = r + 15 ---- (3)
Equating equation (3) in (2), we get
⇒ r + r + 15 = 55
⇒ 2r = 40
⇒ r = 20 cm and h = 35 cm
Using equation (1), we get
⇒ Required curved surface area of cylinder = 2 × (22/7) × 20 × 35 = 4400 cm2