1. **Problem statement:**
We have a dartboard with three concentric circles of radii 2 cm (red), 6 cm (yellow), and 8 cm (green). We want to find:
(a) The probability that a dart hits the red area.
(b) The probability that two darts, thrown one at a time, both hit the yellow area.
2. **Formula and rules:**
The probability of hitting a certain colored area is the ratio of the area of that color to the total area of the dartboard.
Area of a circle is given by $$A = \pi r^2$$.
3. **Calculate areas:**
- Area of red circle: $$A_{red} = \pi \times 2^2 = 4\pi$$
- Area of yellow ring: area between radius 6 and radius 2:
$$A_{yellow} = \pi \times 6^2 - \pi \times 2^2 = 36\pi - 4\pi = 32\pi$$
- Area of green ring: area between radius 8 and radius 6:
$$A_{green} = \pi \times 8^2 - \pi \times 6^2 = 64\pi - 36\pi = 28\pi$$
- Total area of dartboard (largest circle):
$$A_{total} = \pi \times 8^2 = 64\pi$$
4. **(a) Probability of hitting red area:**
$$P(red) = \frac{A_{red}}{A_{total}} = \frac{4\pi}{64\pi} = \frac{4}{64} = \frac{1}{16}$$
5. **(b) Probability both darts hit yellow area:**
Probability of hitting yellow area once:
$$P(yellow) = \frac{A_{yellow}}{A_{total}} = \frac{32\pi}{64\pi} = \frac{32}{64} = \frac{1}{2}$$
Since darts are thrown one at a time independently, probability both hit yellow is:
$$P(both\ yellow) = P(yellow) \times P(yellow) = \left(\frac{1}{2}\right)^2 = \frac{1}{4}$$
**Final answers:**
(a) $$\frac{1}{16}$$
(b) $$\frac{1}{4}$$
Dartboard Probability 34Cf58
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