2. Find the surface area of a sphere of diameter :
(1) 21 cm ( 2 ) 49 cm
(3) 3.5 m
Answers
Answer:
surface area of the sphere = 4πr^2
d=r/2
a) r=10.5 cm
s= 4*3.14*10.5*10.5
s=1384.74cm
b) r=24.5
s= 4*3.14*24.5*24.5
s= 7.539m
c) r= 1.75m
s= 4*3.14*1.75*1.75
s= 25.277m
Given:
Diameter of the sphere :
- 21 cm
- 49 cm
- 3.5 cm
Need to find:
- Surface area of sphere ?
Solution:
1. Diameter of the sphere = 21 cm
Radius of the sphere = Diameter/2
= 21/2
=24.5 cm
As we know that,
⋆ Surface area of sphere = 4πr²
Putting the values,
➜ 4 × 22/7 × 10.5 × 10.5
➜ 4 × 22/7 × 110.25
➜ 1386
2. Diameter of the sphere = 49 cm
Radius of the sphere = Diameter/2
= 49/2
=24.5 cm
As we know that,
⋆ Surface area of sphere = 4πr²
Putting the values,
➜ 4 × 22/7 × 24.5 × 24.5
➜ 4 × 22/7 × 600.25
➜ 7456
3. Diameter of the sphere = 3.5 cm
Radius of the sphere = Diameter/2
= 3.5/2
=1.75 cm
As we know that,
⋆ Surface area of sphere = 4πr²
Putting the values,
➜ 4 × 22/7 × 1.75 × 1.75
➜ 4 × 22/7 × 3.0625
➜ 38.5
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