Question

find find the area of a circle of radius 12 centimetre​

Answer 1

Answer:

Given−

AsectorOABhasitsradiusr=OA=OB=12cm

andthecentralangleAOB=60  

0

.

Tofindout−

ar.segmentAPB=?

Solution−

InΔABCwehaveOA=OB(radiiofthesamecircle).

∴∠OAB=∠OBA⟹∠OAB+∠OBA=2∠OAB.

Now∠AOB+∠OAB+∠OBA=60  

0

+2∠OAB=180  

O

 

(anglesumpropertyoftriangles).

⟹2∠OAB=120  

O

⟹∠OAB=∠OBA=60  

0

.

∴ΔAOBisanequilateralonewithsidea=12cm.

Soar.ΔAOB=  

4

3

​  

 

​  

a  

2

=  

4

3

​  

 

​  

12  

2

cm  

2

=36  

3

​  

cm  

2

.

Againar.sector=  

360  

o

 

θ

​  

×πr  

2

whenθisthecentralangle

&ristheradiusofthesector.

Herer=a=12cmandθ=60  

0

.

ar.sectorAOBP=  

360  

o

 

60  

o

 

​  

×3.14×12  

2

cm  

2

=75.36cm  

2

.

ar.segmentAPB=ar.sectorAOBP−ar.ΔAOB

=(75.36−36  

3

​  

)cm  

2

.

Step-by-step explanation:

Answer 2

Answer:

Step-by-step explanation:

Area of circle = $\pi r^{2}$

22/7 × $12^{2}$

22/7 × 144

3.14 × 144

452.16 $cm^{2}$

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