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Question
A metal container in the form of a cylinder is surmounted by a hemisphere of the same radius. The internal height of the cylinder is 7 m and the internal radius is 3.5 m. Calculate: the total area of the internal surface, excluding the base.
Solution
Radius of the cylinder = 3.5 m
Height = 7 m
Total surface area of container excluding the base = Curved
surface area of the cylinder + area of hemisphere
`= 2 pi"rh" + 2pi "r"^2`
`= (2xx22/7 xx 3.5 xx 7) + (2 xx 22/7 xx 3.5 xx 3.5)`
= 154 + 77 m2
= 231 m2
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