Question

the radius and height of cylinder arr in ratio 7:9 its volume 475.398 cm³ find height and radius
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Answer 1

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Let r,h be radius & hight of cylinder 

   ⇒volume=πr2h,Total surface area (T.S.A)=2πr(h+r)

Given. 

hr=27⇒h=72r

Volume

=πr2h=8316⇒πr2(72r)=8316

   ⇒r3=8316×7×7/2×22=7³×1188/2×22=73×33

    ⇒r=7×3=21cm⇒h=72×21=6cm

T.S.A=2πr=(h+r)=2×22/7×21(6+21)=44×3×27