Find the surface area and total surface area of a hemisphere of radius 21cm.

Explanation

(i) The curved surface area of a hemisphere can be given as `A_C = 2pir^2`

Here, `r = 21 cm`

So, `A_C = 2**22/7**21**21 = 22**26 = 2772cm^2`


(ii) Total Surface Area of a hemisphere, `A_T = `Curved surface area + area of base

So, `A_T = A_C+pir^2`

`A_T = 2272+22/7**21**21 = 2272+22**63`

`A_T = 2272+1386 = 4158 cm^2`