The probability of hitting the third ring is the same as finding what percentage is the area of the third ring out of the total area of the board.
The area of the third ring = The total area of the board - The area of the second circle.
Refer to the diagram below
The diameter for the whole circle = 32 in
The radius = 16 in
The area of the whole circle = π(16)² = 256π
The diameter for the second circle = 22 in
The radius = 11 in
The area of the second circle = π(11)² = 121π
The area of the third ring = 256π - 121π = 135π
Area of the third ring as a percentage of the total area =
= 52.7%
The area of the third ring = The total area of the board - The area of the second circle.
Refer to the diagram below
The diameter for the whole circle = 32 in
The radius = 16 in
The area of the whole circle = π(16)² = 256π
The diameter for the second circle = 22 in
The radius = 11 in
The area of the second circle = π(11)² = 121π
The area of the third ring = 256π - 121π = 135π
Area of the third ring as a percentage of the total area =