Question

What is the total surface area of hemisphere?

• A. $4\pi r^2$
• B. $3\pi r^2$
• C. $\frac{2}{3}\pi r^2$
• D. $\frac{4}{3}\pi r^2$

Answer 1

The correct option is B $3\pi r^2$

Let $r$ be the radius of a hemisphere.

The total surface area of a hemisphere $=$ flat surface area $+$ curved surface area

We know that, the curved surface area of a hemisphere $=2\pi r^2$ and flat surface area $=\pi r^2$

$\therefore$ Total surface area of a hemisphere $=2\pi r^2+\pi r^2=3\pi r^2$

Hence, the total surface area of hemisphere is $3\pi r^2$.