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Surface Areas and Volumes
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27/06/2021 11:59 am
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A cubical block of side 7 cm is surmounted by a hemisphere. What is the greatest diameter the hemisphere can have? Find the surface area of the solid.
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27/06/2021 12:01 pm
It is given that each side of cube is 7 cm. So, the radius will be 7/2 cm.
The total surface area of solid (TSA) = surface area of cubical block + CSA of hemisphere – Area of base of hemisphere
∴ TSA of solid = 6 × (side)2 + 2πr2 - πr2
= 6 × (side)2 + πr2
= 6 × (7)2 + (22/7) × (7/2) × (7/2)
= (6 × 49) + (77/2)
= 294 + 38.5 = 332.5 cm2
So, the surface area of the solid is 332.5 cm2