Question

the volume of a hemisphere is 2425 1/2 .find the curved surface area

Answer 1

Solution:-
Given : Volume of hemisphere = 2425 1/2 cu cm or 2425.5 cu cm.
Volume of hemisphere = 2/3πr³
2425.5 = 2/3*22/7*r³
r³ = (2425.5*21)/44
r³ = 50935.5/44
r³ = 1157.625
r = 10.5 cm
Now, 
Curved Surface Area of hemisphere = 2πr²
= 2*22/7*10.5*10.5
= 693 sq cm
CSA of hemisphere is 693 sq cm.
Answer.

Answer 2

the volume of a hemisphere is 2425 1/2

2/3 (pi)r^3 = 2425 1/2

2/3 (pi)r^3 = 4851/2

r^3 = 4851*3*7/2*2*22

r^3 = 441*21/2*2*2

r^3 = 21*21*21/2*2*2

r^3 = (21/2)^3

taking cube root on both side

r = 21/2

curved surface area = 2(pi)r^2

=2*22*21*21/7*2*2

= 693 cube cm