Question

The volume of a hemisphere is $19404c{m}^3.$ Then, its total surface area is _____.

• A. $4158c{m}^2$
• B. $16632c{m}^2$
• C. $8316c{m}^2$
• D. $3696c{m}^2$

Answer 1

The correct option is A $4158c{m}^2$

Volume of a hemisphere, $V=\frac{2}{3}\pi r^3$

Given: $V=19404c{m}^3$

$\Rightarrow 19404=\frac{2}{3}\pi r^3$

$\Rightarrow 19404=\frac{2}{3}\times \frac{22}{7}\times r^3$

$\Rightarrow r^3=9261$

$\Rightarrow r=21cm$

TSA of the hemisphere $=3\pi r^2$

$=3\times \frac{22}{7}\times {21}^2$

$=4158c{m}^2$