Question

in the given two concentric circles with centre O have radii 21cm and 42 cm if angle AOB =60degree find the area of the shaded region pie =22/7​

Answer 1

Answer:

Radii of inner circle =21 cm=r

Radii of outer circle =42 cm=R

∠AOB=θ=60  

o

 

Area of ring =π(R  

2

−r  

2

)

Area of sector =  

360

θ

​

πr  

2

 

The area of shaded region = Area of ring – Area of ABDC

= Area of ring – [Area of sector of outer circle – Area of sector of inner circle]

=π(R  

2

−r  

2

)−  

1

π(R  

2

−r  

2

)

​

×  

360

θ

​

 

=π[R  

2

−r  

2

](1−  

360

θ

​

)

=  

7

22

​

[42  

2

−21  

2

](1−  

360

60

​

)

=3465 cm  

2

mark me as brainliest