The total surface area of a hemisphere is$7392 {\text{cm}}^2$, then the radius of the hemisphere is

 $\left(\text{Take }\pi =\frac{22}{7}\right)$.

Concept: We know the total surface area of a hemisphere$=3\pi r^2$.

Here, $3\pi r^2=7392$

$\Rightarrow 3\times \frac{22}{7}\times r^2=7392$

$\Rightarrow r=28\text{cm}$

Hence, the radius of the hemisphere is $28 \text{cm}$.