Question

05
If the radius of a sphere is
doubled, then the ratio of
surface areas of original
sphere to that of the
required sphere is​

Answer 1

ᕚ( คภรฬєг )ᕘ

S₁=4πr²

S₂=4π(2r)²

=16πr²

$\frac{S₂}{S₁}$=$\frac{16πr²}{4πr²}$=$\frac{4}{1}$=4:1

Answer 2

Step-by-step explanation:

Surface area of a sphere with radius r = 4πr^2

Surface area of a sphere with radius (R) = 4πR^2

Here R = 2r

Ratio = 4πr^2 / 4πR^2

= 4πr^2 / 4π(2r)^2

= 4πr^2 / 4π4r^2

Now in both numerator and denominator 4π is there so we can cancel them