Question

A vessel is in the form of a hollow hemisphere mounted by a hollow cylinder. The diameter of the hemisphere is 14 cm and the total height of the vessel is 13 cm. Find the inner surface area of the vessel. [Use $\pi=\frac{22 }{7}$ ]

Answer 1

It can be observed that radius (r) of the cylindrical part and the hemispherical part is the same (i.e., 7 cm).
Height of hemispherical part = Radius = 7 cm
Height of cylindrical part (h) = 13 −7 = 6 cm
Inner surface area of the vessel = CSA of cylindrical part + CSA of hemispherical part
$=2\pi rh+2\pi r^2$
Inner surface area of the vessel =$(2\pi rh+2\pi r^2)$ cm2 = $2\pi r(h+r)$ cm2
$= 2×(\frac{22}{7})×7(6+7)$cm2 = 572 cm2