Question

The altitude of a cylinder is increased six times and the bse area is decreased by one-ninth of its value. The factor by which its C.S.A. increases is a)2/3 b)1/2 c)3/2 d)2

Answer 1

Answer:

(d) 2

Step-by-step explanation:

old altitude = x

new altitude = 6x

old area = y

πr² = y

r = √(y/π)

new area = 1/9y

πr² = 1/9y

r = √(y/3π)

old csa = 2π√(y/π)x

            = 4πyx²

new csa = 2π√(y/3π)6x

              = 4πy2x²

increase = 2