Question

find the radius of a circle whose area is equal to the sum of the areas of three circles whose radii are 3 cm 4 cm and 12 CM​

Answer 1

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Answer 2

Answer:

Given

Radius of 1st circle = 3 cm

Radius of 2nd circle = 4 cm

Radius of 3rd circle = 12 cm

We know that

Area of circle = πr²

Area of 1st circle = πr²

===> 22 / 7 × ( 3 )²

===> 22 / 7 × 3 × 3

===> 22 / 7 × 9

===> 198 / 7

===> 28.285714 cm²

Area of 2nd circle = πr²

===> 22 / 7 × ( 4 )²

===> 22 / 7 × 4 × 4

===> 22 / 7 × 16

===> 352 / 7

===> 50.285714 cm²

Area of 3rd circle = πr²

===> 22 / 7 × ( 12 )²

===> 22 / 7 × 12 × 12

===> 22 / 7 × 144

===> 3168 / 7

===> 452.57143 cm²

Sum of areas of three circles

28.285714 + 50.285714 + 452.57143

531.14286 cm² .