Question

19) If the radius of a sphere is doubled. What is the ratio of the surface area of the original sphere to the new one?​

Answer 1

radius of first sphere =r

radius of second sphere =2r

ration if surface area

= 4πr/4πR

r/R

r/2r

1/2 = Ans

Answer 2

Step-by-step explanation:

let the radius be r

now new radius will be 2r

SA of sphere is 4pai r^2

=4×22/7×r×r

new S A willbe 4×22/7×2r×2r

now dividing it then

4×22/7×r×r/4×22/7×2r×2r

=1/4

so the ratio will be

1:4