If the length of the radii of two solid right circular cylinder are in the ratio 2:3 and their heights are in the ratio 5:3 , then the ratio of their lateral surfaces isA. `2:5`B. `8:7`C. `10:9`D. `16:9`

If the length of the radii of two solid right circular cylinder are in

1.	If the length of the radii of two solid right circular cylinder are in the ratio 2:3 and their heights are in the ratio 5:3 , then the ratio of their lateral surfaces isA. `2:5`B. `8:7`C. `10:9`D. `16:9`
Answer» Correct Answer - C Let the radii of two solid right circular cylinders are 2x units and 3x units, such that their ratio is `2x:3x=2:3`, which satisfies the given condition. Also let their heights be 5 h units and 3h units respectively. `:.` the area of the lateral surface of the first `=2pi xx 2x xx 5h` sq-units `=20 pi x h ` sq-units. and the area of the lateral surface of the second `=2pi xx 3x xx 3h` sq-units `=18pi x h ` sq-units. Hence the required ratio `=2pi xx h : 18 pi x h = 10:9` `:.` (c) is correct.