Question

, if the radius of the circles with
centres O and O' is lcm cach, what is the perimeter
of the shaded portion of the ligure​

Answer 1

Answer:

Step-by-step explanation:

We have,

Area of ring =π(R  

2

−r  

2

)

=π×(14  

2

−7  

2

)

=462cm  

2

 

Area of the region ABDC

=Area of sector AOC-Area of sector BOD

=(  

360

40

​  

×  

7

22

​  

×14×14−  

360

40

​  

×  

7

22

​  

×7×7)cm  

2

 

=(  

9

1

​  

×22×14×2  

9

1

​  

×22×7×1)cm  

2

 

=  

9

22

​  

×(28−7)cm  

2

=  

3

154

​  

cm  

2

 

Hence, Required shaded area

=(462−  

3

154

​  

)cm  

2

 

=  

3

1232

​  

cm  

2

=410.67cm  

2

Answer 2

Answer:

perimeter of arc BOA+perimeter of arc AO'B

=theta/360×2πr +theta/360×2πr