Question

Hey.....plzzzzzzz answer it.....its important

The radii of two cylinders are in ratio 5:3 and heights are in ratio 5:3. Calculate the ratio of their curved surface area.

***plz answer other questions in my ptofile.***

Answer 1

The Curved surface area of cylinder = 2Πrh

let the rardius & height ratio of 1st cylinder to 2nd cylinder be 5x, 3x

so ,
$\frac{curved \: surface \: area \: of \: 1st \: cylinder}{curved \: surface \: area \: of \: 2st \: cylinder}$

putting the values

$\frac{2 \times 3.14 \times 5x \times 5y}{2 \times 3.14 \times 3x \times 3y}$

on solving we get,

=> 25/9 the simplest ratio

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Answer 2

Let the radii of the cylinders be 2x and 3x respectively.

And let their heights be 5y and 3y respectively.

CSA of 1st cylinder=2πrh=2π×2x×5y

CSA of 2nd cylinder=2πRH=2π×3x×3y

∴Ratio of CSA of the 2 cylinders=2π×2x×5y÷2π×3x×3y

                                                     =10xy÷9xy

                                                     =10/9

Volume of 1st cylinder= πr²h=π×4x²×5y

Volume of 2nd cylinder= πR²H=π×9x²×3y

∴Ratio of the volume of the 2 cylinders=π×4x²×5y÷π×9x²×3y

                                                                =4×5÷9×3=20÷27=20/27

 
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