Question

if the radius of cylinder is doubled and the height is Halved. what is the ratio between the new curved surface area and the previous curved surface area of the cylinder

Answer 1

perivous cylinder
r=r
h=h
CSA of cylinder=2×22/7×r×h

new cylinder
r=2r
h=1/2h
CSA of new cylinder=2×22/7×r×h
=2×22/7×2r×1/2h
=2×22/7×r×h
ratio of CSA of new cylinder to ratio of CSA of previous cylinder=CSA of new cylinder/CSA of prious cylinder
=2×pie×r×h/2×pie×r×h
=1:1