Radius of hemisphere is thrice than that of sphere. What is the ratio of Total surface area of hemisphere to that of sphere?

27 : 4

r = radius of hemisphere

R = radius of sphere

r = 3R

\(\frac{r}{R}\) = \(\frac{3}{1}\)

T.S.A. (Total Surface Ares) of hemisphere = 3\(\pi \)r²

                                         T.S.A. of sphere = 4\(\pi \)R²

Ratio ⇒   3\(\pi \) × (3)²    :     4\(\pi \) × (1)² = 27  :   4