Question

The thickness of a hemispherical bowl is 0.25cm. the inner radius of the bowl is 5 cm. Find the outer curved surface area of the bowl. (Take π = 22/7)

Answer 1

Hint: To calculate the outer curved surface area of the bowl there are some steps :
(i)First, We have to calculate the outer radius.
(ii)Then we apply the formula of the curved surface area of the hemisphere.

Complete step-by-step answer:
 The inner radius of the bowl = 5cm
The thickness of the bowl = 0.25c,

Outer radius of bowl = inner radius +thickness = 5+0.25 = 5.25 cm
The formula of the curved surface area of the hemisphere = \[2\pi {r^2}\]
So, the outer curved surface area of the bowl = \[2\pi {r^2}\]
\[
  2 \times \dfrac{{22}}{7} \times {(5.25)^2} \\
   = 2 \times \dfrac{{22}}{7} \times 5.25 \times 5.25 = \dfrac{{1212.75}}{7} \\
   = 173.25c{m^2} \\
\]
∴ The outer curved surface area of hemispherical bowl = 173.25 $c{m^2}$.
Note: The curved surface area of the hemisphere is the outer surface area of hemisphere
We can find the surface area of the hemisphere. Since the base of the sphere is circular in shape, there are two types of areas, one is total surface area and other is curved surface area.
We can easily calculate the curved surface area of the hemisphere
Since hemisphere is half of sphere
∴ the curved surface area of hemisphere = half of the surface area of a sphere
CSA = $\dfrac{1}{2}4\pi {r^2}$
CSA = $2\pi {r^2}$
So, the curved surface area of hemisphere = $2\pi {r^2}$