Question

TSA of hemisphere is 5940. Find its diameter.

Answer 1

T.S.A of hemisphere = $2\pi r^2+\pi r^2=3\pi r^2$

$\Rightarrow 3\pi r^2=5940\Rightarrow 3\times \frac{22}{7}\times r^2=5940\Rightarrow r^2=\frac{5940\times 7}{22\times 3}$

$\Rightarrow r^2=630\Rightarrow r=\sqrt{630}=\sqrt{7\times 9\times 10}=3\sqrt{70}$

$\Rightarrow$ diameter = $2r=6\sqrt{70}$