Question

the radio of two circular cylinders are in the radio 2:3 and their height are in radio 5:4 calculate the ratio of curved surface area

Answer 1

r1/r2 = 2 / 3
h1/h2 = 5/4 

CSA1/CSA2 = 2$\pi$r1h1 / 2$\pi$ r2h2
                     = r1/r2 x h1/h2
                     = 2/3 5/4
                     = 10/12
                     = 5/6

CSA1 : CSA2 = 5:6