Question

volume and surface area of a solid hemisphere are numerically equal. what is diameter of hemisphere

Answer 1

Volume of hemisphere = S.A of hemisphere 
2/3πr^3=3πr^2
2/3r=3
r=9/2
diameter =9/2x2
=9

Answer 2

Here, by condition

Volume of hemisphere = Surface area of hemisphere

If the radius is r, then

2/3πr^3 = 3πr^2

2/3r = 3

r = 9/2 = 4.5 cm

Now, 2r = diameter

diameter = 4.5*2 = 9cm