Find the total surface area of a hollow hemispherical bowl of diameter 14 cm and negligible thickness.

Inner radius = r =$$\frac{D}{2}$$ = 7 cm

Outer radius = R = 7+0 = 7 cm thickness = 0 cm

Inner curved surface area = 2 π r²

Outer curved surface area = 2 π R²

On the base of hemispherical bowl, there is a flat ring area too.

Area of flat ring : $$\pi\times R^2 - \pi\times r^2$$

Total surface area: $$2\times \pi \times r^2 + 2\pi \times R^2 + \pi \times R^2 - \pi \times r^2$$

= $$3\pi \times R^2 + \pi \times r^2 $$

= $$3\pi \times 7^2 + \pi \times 7^2 $$ = 616 cm²