Question

Two cylinder have their radii in the ratio 4 : 5 and their height in the ratio 5 : 6 . find the ratio of their curved surfaces areas.

Answer 1

R1=4, R2=5. H1=5, H2=6
Curved surface area =2*22/7*20/2*22/7*30
=20/30
=2:3

Answer 2

Answer:

Step-by-step explanation:

case1

radius= 4x

height=5y

Curved surface area = 2*pi*r*h

=2*pi*4x*5y

Case 2

radius=5x

height=6y

Curved surface area = 2*pi*5x*6y

Case1/Case2 = 2*pi*4x*5y/2*pi*5x*6y

( simplification = cancel 2 to 2 and pi to pi and x to x and y to y)

=4*5/5*6

20/30 ( simplification )

2: 3