Question

Diameter of a hemisphere is 28 cm. Find its curved surface area and total surface

area.​

Answer 1

Given :

Diameter of a hemisphere is 28 cm

To find :

Find its curved surface area and total surface

Solution :

radius = Diameter ÷ 2

= 28 ÷ 2

= 14

Curved surface area of hemisphere = 2πr²

= 2 x 22/7 x (14)²

= 2 x 22/7 x 196

= 2 x 22 x 28

= 1232 sq cm

total surface area = 3πr

= 3 x 22/7 x 14

= 3 x 22 x 2

= 132 cm²

=> curved surface area is 1232 sq cm and total surface area is 132 cm²

Answer 2

ᎯᏁᏕᏯᎬᏒ

Diameter = 28 cm

Radius = 28/2 = 14 cm

$\purple{.................................................}$

$\boxed{ \rm {CSA \: of \: hemisphere = 2\pi r² }}$

$\sf CSA \: of \: hemisphere = 2 \times \frac{22}{7} \times 14 \times 14$

$\sf CSA \: of \: hemisphere = 2 \times 22 \times 2\times 14$

${\therefore}~ \sf CSA \: of \: hemisphere = \red{1232 \: {cm}^{2}}$

$\purple{.................................................}$

$\boxed {\rm {TSA \: of \: hemisphere = 3\pi r}}$

$\sf TSA \: of \: hemisphere = 3 \times \frac{22}{7} \times 14$

${\therefore}~ \sf TSA \: of \: hemisphere = \red{132 {cm}^{2}}$