If radii of two cylinders are in the ratio 4 : 3 and their heights are in the ratio 5: 6, find the ratio of their curved surfaces.
The ratio in radii of two cylinders = 4 : 3
and ratio in their heights = 5: 6
Let r1 and r2 be the radii and h1,h2 be their heights respectively.
∴ r1 : r2 = 4:3 and h1 : h2 = 5:6
∴ `r_1 = 4/3 "and" (h_1)/(h_2) = 5/6`
∴ Surface area of the first cylinder = `2pir_1h_1`
and area of second cylinder = `2pir_2h_2`
`(2pir_1h_1)/(2pir_2h_2) = r_1/r_2 xx h_1/h_2 = 4/3 xx 5/6 = 20/18`
= `10/9 = 10 : 9`
∴ Ratio in their surface areas = 10 : 9
Concept: Surface Area of a Cuboid
Is there an error in this question or solution?
In eduladder you can Ask,Answer,Listen,Earn and Download Questions and Question papers.Watch related videos of your favorite subject.
Connect with students from different parts of the world.
Apply or Post Jobs, Courses ,Internships and Volunteering opportunity. For FREE
See Our team
Wondering how we keep quality?
Got unsolved questions? Ask Questions
>
The radii of two cylinders are in the ratio 2:3 and their heights are in the ratio 5:3. Calculate the ratio of their volumes.
Solution
Ratio of radii of two cylinders =2:3
and the ratio of heights =5:3
Let r1,h1 and r2,h2 be the radii and heights of two cylinders respectively.
∴r1r2=23 and h1h2=53
Now Volume~of~first~cylinderVolume~ of~second~cylinder=π(r1)2h1π(r2)2h2
=(r1r2)2×(h1h2)
=(23)2×53
=49×53=2027
Mathematics
RD Sharma
Standard VIII
65