Question

What's the ratio between the total surface areas of the 2 hemispheres if $\frac{r_1}{r_2}=\frac{1}{2}$?

• A. $\frac{1}{8}$
• B. $\frac{8}{1}$
• C. $\frac{1}{4}$
• D. $\frac{4}{1}$

Answer 1

The correct option is C $\frac{1}{4}$

We know that,
total surface area of hemisphere
$=3\pi r^2$

Given,
$\frac{r_1}{r_2}=\frac{1}{2}$

Now,

$=\frac{totalsurfaceareaof1sthemisphere}{totalsurfaceareaof2ndhemisphere}$

$=\frac{3\pi (r_1{)}^2}{3\pi (r_2{)}^2}$

$=\frac{1}{4}$