Question

*The total surface area of a hemisphere of diameter 42 cm is ______.*

1️⃣ 396 sq. cm
2️⃣ 4158 sq. cm
3️⃣ 5544 sq. cm
4️⃣ 528 sq. cm​

Answer 1

Given :

• Radius of Heimsphere is 42 cm.

To Find :

• Total Surface Area of Hemisphere .

Solution :

$\longmapsto\tt{Radius=\dfrac{42}{2}=21\:cm}$

Using Formula :

$\longmapsto\tt\boxed{T.S.A\:of\:Hemisphere=3\pi{{r}^{2}}}$

Putting Values :

$\longmapsto\tt{3\times\dfrac{22}{{\cancel{7}}}\times{{\cancel{21}}}\times{21}}$

$\longmapsto\tt{66\times{3}\times{21}}$

$\longmapsto\tt\bf{4158\:{cm}^{2}}$

So , Total Surface Area of Hemisphere is 42 cm..

Option 2) 4158 cm² is Correct..

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• C.S.A of Hemisphere = 2πr²
• T.S.A of Hemisphere = 3πr²
• Volume of Hemisphere = 2/3 πr³
• Surface Area of Sphere = 4πr²
• Volume of Sphere = 4/3 πr³

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