Let R ans r be the outer and inner radii of the hemisphere.

Now,its curved surface area=outer surface area+inner surface area

$2R^{2}\times2r^{2}$

$=2\pi (R^{2}+r^{2})sq.units$

$Total surface area=outer surface area+inner surface area+Area at the base$

$=2\pi R^{2}+2\pi r^{2}+\pi (R^{2}-r^{2})$

$=2\pi (R^{2}+r^{2})+\pi(R+r)(R-r)sq.units$

$=\pi(3R^{2}+r^{2})sq.units$