1st circle ⟶ with radius 3
2nd circle ⟶ with radius 7
3rd circle ⟶ with radius 9
Area of 1st circle = (3)2 = 9π
Area of 2nd circle= (7)2 = 49π
Area of 3rd circle = (9)2 = 81π
Area of shaded region = Area of 2nd circle – area of 1st circle
= 49π – 9π
= 40π
Probability that will land on the shaded region = (area of shaded region)/(area of 3rd circle) =40π/81π = 40/81