Question

The diameter of basketball is 4 times the diameter of the tennis ball. Then, the ratio of surface area of basketball to that of tennis ball is.

• A. $16:1$
• B. $1:16$
• C. $8:1$
• D. $1:8$

Answer 1

The correct option is A $16:1$

Let,
the diameter of the tennis ball be $d$.
then diameter of the basketball ball is $4d$.

We know that,
Surface area of sphere
$=4\pi r^2$

Now,
$=\frac{\text{Surface area of the basketball}}{\text{Surface area of the tennis ball}}$
$=\frac{4\pi (\frac{4d}{2}{)}^2}{4\pi (\frac{d}{2}{)}^2}$
$=\frac{16}{1}$
$=16:1$