Question

if the curved surface area of a solid hemisphere is 2772cm2, then find its total surface area.

Answer 1

Given,

CSA = 2772 cm^2

=>2π${r}^{2}$ = 2772

=> 2 × $\frac{22}{7}$ × ${r}^{2}$ = 2772

=> $\frac{44}{7}$ × ${r}^{2}$= 2772

=> ${r}^{2}$ = $\frac{2772 × 7}{44}$

=> ${r}^{2}$ = 63 × 7

=> ${r}^{2}$ = 441

=> r = √441

$\therefore$ r = 21 cm


$\therefore$ TSA = 3π${r}^{2}$

= 3 × $\frac{22}{7}$ × ${21}^{2}$

= 3 × $\frac{22}{7}$ × 441

= 3 × 22 × 63

=4158 ${cm}^{2}$

$\huge{answer = 4158 {cm}^{2} }$