Question

What is the diameter (in cm) of a sphere whose surface area is 616${\text{cm}}^2$?

• A. 14
• B. 7
• C. 28
• D. 21

Answer 1

The correct option is A

14

Surface area of sphere =
$4\pi r^2=616\Rightarrow r^2=616\times \frac{7}{22}\times \frac{1}{4}\Rightarrow r^2=49\Rightarrow r=\sqrt{49}\Rightarrow r=7\text{cm}$

$\therefore$ The diameter, $D=2r=2\times 7=14\text{cm}$