A hemisphere of lead of radius 9 cm is cast into a right circular cone of height 72 cm. Find the radius of the base of the cone.
Given,
Radius of hemisphere = (R) = 9 cm
Height of cone = 72 cm
Let radius of cone = r cm
We know that,
Volume of hemisphere = volume of cone
= 
πR3 = 
πr2h
= 
= r2 × 72
= r2 = 
= r = 
Radius of base of cone = 4.5 cm.
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