Question

The dartboard represented below has 3 circular areas with point values of 10, 6, and 4 points. The radii of the circles are 3 inches, 6 inches, and 9 inches. Which is closest to the area of the region that is worth 4 points?

226 in.^2
63 in.^2
113 in^2
141 in.^2
Please! If you could at least find the formula to do this problem that would be great.

Answer 1

141 in²

Explanation:

Outer circle - middle circle

3.14 × (9² - 6²)

3.14 × 45

141.3 in²

Answer 2

141 in.^2

Explanation:

First find the area of the full circle

The radii is 9 inches

A = pi r^2

A = 81 pi

Then find the area of the next smallest circle which is 6 inches

A = pi r^2

A = 36 pi

Subtract the difference to get the area of the blue

81pi - 36 pi

45 pi

45 * 3.14

141.3