The height of a cone is 21 cm.Find the area of the base if the slant height is 28 cm.
Height of the cone (h)=21 cm
Slant height (l) = 28 cm
∴l2=r2+h2⇒r2=l2−h2=(28)2−(21)2=784−441=343 ...(i)Now area of base=πr2=227×343 [From(i)]=22×49=1078 cm2
The curved surface area of a right circular cone whose slant height is 28 cm and base radius is 10.5 cm is
The volume of a right circular cone is 9856 cm3.If the diameter of the base is 28 cm,find:
(i) height of the cone
(ii) slant height of the cone
(iii) curved surface area of the cone.