Question

the ratio of the whole surface area of a solid sphere and a solid hemisphere is

Answer 1

now ratio is gavien as follows
$surface \: area \: of \: sphere \: is \: same \: as \: its \: curved \: surface \: area \: \: \\ \\ surface \: area \: of \: sphere \: = 4\pi {r }^{2} \\ \: now \: surface \: area \: of \: hemisphere \: is \: same \: as \: ts \: curved \: surface \: area \: \\ \: \: surface \: are \: of \: \: hemisphere = 2\pi {r }^{2} \\ \: now \: ratio \: is \: \\ \: \: = \frac{4\pi {r}^{2} }{2\pi {r}^{2} } \: = \frac{2}{1} = 2 is \: to \: 1$
now ratio is 2:1