Surface area of circles

Question

In which sphere is the ratio surface area/volume greater? 

A.) A smaller Sphere

B.) A larger Sphere

Answer 1

SA = 4πr²          and          V = (4/3)πr³

 

 

Divide SA by V to obtain the ratio.

 

(4πr²) / [(4πr³) / 3] =

 

(4πr²) * [3 / (4πr³)] =

 

3/r

 

 

Let's select r = 2  and r = 3. Then substitute these values into the ratio.

 

 

Ratio for smaller sphere:

 

3/2 = 1.5

 

Ratio for larger sphere:

 

3/3 = 1

 

 

By comparing the ratios, your answer is (A).