Question

The total surface area of a hemisphere is 166.32 sq cm, find its radius?

Answer 1

Given:

Total surface Area of hemisphere= 166.32 cm²

Total surface Area of hemisphere= 3πr²

166.32 = 3 × (22/7) × r²

166.32× 7 = 66× r²

1164.24 = 66 r²

r² = 1164.24/66

r²= 17.64

r= √ 17.64 =√(1764/100) =42/10= 4.2 cm

Hence, the radius of the hemisphere is = 4.2 cm

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Hope this will help you.....

Answer 2

from the given data we know that total surface area of hemisphere = 166.32 cm² 
Also we know that the equation
That the total surface area of hemisphere= 3πr²
Put the surface area value
  Hence     166.32 = 3*22/7*r²
also , by furthur calculations
So ,166.32*7 =66 *r²
 and ,166.32*7/66 = r²

so the 17.64= r²
By taking square root on both side
we will get √17.64 = √r²
So  , 4.2 = r
thus the radius will be 4.2 cm which is our answer.