Math, asked by dipalisamaddar9249, 6 months ago

please answer both........ it's urgent ​

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Answered by brainist100
1

Answer:

20.

the length of ab is 10.5

Area of big circle = 154 cm 2

Area of circle = π r 2

therefore , π r 2 = 154

22 / 7 r 2 = 154

r 2 = 49

therefore , r = 7

The radius of big circle is 7 units

Radius of big circle + radius of small circle = 10. 5

7 + radius of small circle = 10.5

therefore , radius of small circle is 3.5

Area of small circle = π r 2

Area of small circle = 22/7 ( 3.5) 2 ( this 2 is square )

Therefore area of = 38. 5 cm 2

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