volume

external diameter=30 cm

 So external radius =15 cm

Thickness =2cm

So internal radius = external radius - thickness =15-2=13 cm

So volume of copper in the  hemispherical  solid=external volume - internal volume

=

Find this quantity, it'll be  in cu cm.

Multiply this by 7, as it's given that 1 cu cm of copper weighs 7 gm.

That will be the final answer.

 

 

 

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