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Question
A rocket is in the form of a circular cylinder closed at the lower end and a cone of the same radius is attached to the top. The radius of the cylinder is 2.5 m, its height is 21 m and the slant height of the cone is 8 m. Calculate the total surface area of the rocket.
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Solution
Radius of the cylinder = 2.5 m
Height of the cylinder = 21 m
Curved surface area of the cylinder `= 2pirh = 2xx22/7xx2.5xx21=330` m2
Radius of the cone = 2.5 m
Slant height of the cone = 8 m
Curved surface area of the cone `= pirl = 22/7 xx2.5xx8 = 62.86` m2
Area of circular base = `pir^2 = 22/7xx2.5xx2.5xx=19.643`
∴ Total surface area of rocket = 330 + 62.86 + 19.643 m2
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