Question

find R of a sphere whose surface area
is 154 cm².​

Answer 1

Answer:

Let x be radius

⇒Surface Area =154cm

2

∴4πx

2

=154

⇒x

2

=

4×22

154×7

=

4

49

⇒x=

4

49

x=3.5cm

Step-by-step explanation:

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Answer 2

Given

• Surface area of a sphere

To find

• Radius of the sphere

Solution

To find radius of the sphere, we will use the formula of area of the sphere and find its value.

Using formula,

❖ Area of sphere = 4πr²

where,

• Take π = 22/7
• r = radius of the sphere

Substituting the given values,

⟶ 154 = 4 × 22/7 × r²

⟶ 154 = 88/7 × r²

⟶ 154 × 7/88 = r²

⟶ 12.25 = r²

⟶ √12.25 = r²

⟶ ± 3.5 Reject - ve = r

⟶ r = 3.5 cm

❖ Radius of the sphere = 3.5 cm

__________________________________

Let's verify :-

Using formula,

Area of the sphere = 4πr²

Substituting the values,

⟶ 4 × 22/7 × 3.5 × 3.5

⟶ 154 cm²

Hence, verified.