A solid is in the shape of a frustum of a cone. The diameters of the two circular ends are 60 cm and 36 cm and the height id 9 cm. Find the area of its whole surface and the volume.
Given: height of the frustum = 9cm
Radius of its lower and upper ends: r’ = 30cm and r’’ = 18cm
Let slant height be l
Slant height, l = 
⇒ l = 15cm
Volume = 
= 5292 π cm3
Total surface area = π(r’ + r’’)l + π r’2 + π r’’2
= π(30 + 18)15 + π (30)2 + π (18)2
= 1944π cm2
16