Question

the radius of two concentric circles are 9cm and 12 cm respectively .find the area of the circular path between two circles?
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Answer 1

Step-by-step explanation:

Area of first circle =81π

Area of 2nd circle =144π

Area of 3rd circle =255π

Let radius of 3rd circle =R

∴πR

2

=225π

R

2

=225

R=15

∴ Circumference =2×π×15=30πcm.

Answer 2

Area of first circle =81π

Area of 2nd circle =144π

Area of 3rd circle =255π

Let radius of 3rd circle =R

∴πR

2

=225π

R²=225

R=15

∴ Circumference =2×π×15=30π cm.