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
From the figure:
The greatest diameter possible for the hemisphere is equal to the cube's edge= 7cm
Radius (r) of hemispherical part = 
= 3.5cm
Total surface area of solid = Surface area of cubical part + CSA of hemispherical part - Area of base of hemispherical part
= 6 (Edge)2 + 2πr2 – πr2
= 6 (Edge)2 + πr2
Total surface area of solid = 6 (7)2 + 
* 
* 
= 294 + 38.5
= 332.5 cm2
26