Question

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.​

Answer 1

➝ Given

Edge of Cube = 7 cm

Diameter of hemisphere = 7 cm

Radius of hemisphere = 7/2 cm

➝ Find

surface area of solid

➝ Solution

➢. 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

➝ Formula used ;-

Area of cube = 6a2

CSA of hemisphere = 2πr2