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Question
Two right circular cylinders of equal volumes have their heights in the ratio 1 : 2. What is the ratio of their radii?
Solution
Let the radii of the two cylinders be r and R; and height be h and we have,
`"h"/"H" = 1/2` ...........(i)
Volume of the first cylinder = Volume of the second sphere
⇒ πr2 H = πR2 H
`⇒ "h"/"H" = "R"^2/"r"^2`
`=> 1/2 = "R"^2/"r"^2`
`=> "r"^2/"R"^2 = 1/2`
`=> ("r"/"R")^2=1/2`
`=>"r"/"R" = sqrt(2/1)`
`∴ "r" : "R" =sqrt(2:1)`
So, the ratio of their radii is `sqrt(2)` : 1.
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