Question

The radius of two spheres are in the ratio 2:3. what is the ratio of their surface

Answer 1

The ratio of radii of two spheres is givenas 2:3

So,
Let the radius of sphere 1 be 2x
So,
Radius of second sphere is 3x

Now,

For a sphere:-
Total surface area is equal to 4* pie* r^2

So,

For sphere 1
Surface area = 4*pie * (2x)^2 = 4* pie * 4x^2


For sphere 2
Surface area = 4*pie* (3x)^2 = 4 * pie * 9x^2


So,

The ratio between their surface area is:-

4*pie*4x^2/4*pie*9x^2
= 4/9

So,
The ratio of their surface area is 4:9