Question

is radii of two cylinder are in the ratio 4:3 and the height are in the ratio 5:6 find the ratio of their curved surface

Answer 1

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we have given that :
Radius of cylinder are in ratio = 4:3
and
Height of cylinder are in ratio = 5:6

we have to find :
Ratio between their curved surface areas??

solution:-
we know that :
curved surface area of cylinder = 2πrh

here,
according to given:
let radius of 1st cylinder = 4r
and
height of 1st cylinder = 5h

and
radius of 2nd cylinder = 3r
and
height of 2nd cylinder = 6h

now,
C.S.Area of 1st cylinder = 2π(4r)(5h)

= 20× 2πrh

and
C.S.Area of 2nd cylinder = 2π(3r)(6h)

= 18×2πrh

=> Ratio between their curved surface areas = C.S.Area of 1st cylinder / C.S.Area of 2nd cylinder

=> 20×2πrh /18×2πrh

=> 20/18

=> 10/9 answer
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⭐✡ hope it helps:)