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Question
The radii of two cylinders are in the ratio 3 : 5 and their heights are in the ratio 2 : 3. What is the ratio of their curved surface areas?
Solution
Given that, `r_1 :r_2 = 3:5 " and " h_1 : h_2 = 2 : 3`
Now, the ratio of their curved surface area
`s_1 :s_2 = 2pir_1h_1 : 2 pir_2h_2`
`s_1 :s_2 = 2pir_1 h_1 : 2pir_2 h_2`
`(s_1)/s_2 = (2pir_1h_2)/(2pir_2h_2)`
`=(r_1 /r_2) (h_1/h_2)`
`(s_1)/s_2 = 3/5 xx 2/3 = 2/5`
Hence , `s_1 :s_2 = 2 : 5`
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