Question

Q1) in the cylinder, radius is doubled and the height is halved. The curved surface area will be : four times or doubled or same
Q2) simplify, using suitable property : 9/6*3/5+(-5/8)-9/6*4/9

Answer 1

1
in a cylinder
r=2r. h=h÷2
Cs=2πrh=2π×2r×(h÷2)
=2πrh
Cs will remain same

2
.

Answer 2

1. four times

previous radius =r
height=h

now
radius=2r
height =h/2

surface area=2πrh

new surface area=2π(2r)(h/2)

2π*2r*h

answer= four times of previous area