Question

The total surface area of hemisphere is 4158 square cm find its diameter

Answer 1

Let the radius of hemisphere be a

TSA of hemisphere = 3 pi a^2

=> 4158 = 3 × 22 a^2 / 7

=> a^2 = 4158 × 7 / 66

=> a^2 = 63 × 7

=> a^2 = 9× 7 × 7

=> a = 3× 7

=> a = 21

Radius = 21 cm

Diameter = 2 × 21 = 42 cm

Answer 2

Answer:

The diameter is 42 cm.

Step-by-step explanation:

Given : The total surface area of hemisphere is 4158 square cm.

To find : Its diameter ?

Solution :

The total surface area of the hemisphere is $SA=3\pi r^2$

Where, r is the radius of hemisphere

SA=4158 square cm is the surface area

Substitute the value in the formula,

$4158=3\pi r^2$

$\frac{4158}{3\pi}=r^2$

$r^2=441$

$r=\sqrt{441}$

$r=21$

The diameter is $d=2r=2(21)=42$

Therefore, The diameter is 42 cm.