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Question
If the radii of circular ends of a bucket 24cm high are 5cm and 15cm. find surface area of
bucket?
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Solution
Given height of a bucket(R) = 24cm
Radius of circular ends of bucket 5cm and 15cm
r1 = 5cm ; r2 = 15cm
Let 'l' be slant height of bucket
`l=sqrt((r_1-r_2)^2+h^2)`
⇒`l=sqrt((15-5)^2+24^2`
⇒`l=sqrt(100+576) =sqrt(676)`
l=26cm
Curved surface area of bucket `=pi(r_1+r_2)l+pir_2^2`
= π(15+5)26+π(5)2
= π(20)26+π(5)2
= π(520+25)
= 545π cm2
∴ Curved surface area of bucket = 545π cm2
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