Radius of hemisphere is thrice than that of sphere. What is the ratio of Total surface area of hemisphere to that of sphere?
Answer & explanation
Correct answer: option 1
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