1. **State the problem:**
We have a lighthouse beacon 141 feet above water. From point A, the angle of elevation to the beacon is 6°. From point B, closer to the lighthouse, the angle is 12°. We need to find the distance from A to B.
2. **Set up the scenario:**
Let the distance from point A to the lighthouse base be $x$ feet.
Let the distance from point B to the lighthouse base be $y$ feet.
The distance from A to B is then $x - y$.
3. **Use the tangent function:**
Since the lighthouse height is opposite and the distance along the water is adjacent, we use:
$$\tan(\theta) = \frac{\text{opposite}}{\text{adjacent}}$$
From point A:
$$\tan(6^\circ) = \frac{141}{x} \implies x = \frac{141}{\tan(6^\circ)}$$
From point B:
$$\tan(12^\circ) = \frac{141}{y} \implies y = \frac{141}{\tan(12^\circ)}$$
4. **Calculate $x$ and $y$:**
$$x = \frac{141}{\tan(6^\circ)}$$
$$y = \frac{141}{\tan(12^\circ)}$$
5. **Find distance from A to B:**
$$\text{Distance} = x - y = \frac{141}{\tan(6^\circ)} - \frac{141}{\tan(12^\circ)}$$
6. **Evaluate using approximate tangent values:**
$$\tan(6^\circ) \approx 0.1051$$
$$\tan(12^\circ) \approx 0.2126$$
So,
$$x \approx \frac{141}{0.1051} \approx 1342.53$$
$$y \approx \frac{141}{0.2126} \approx 663.12$$
Distance:
$$1342.53 - 663.12 = 679.41$$
7. **Round to nearest foot:**
$$\boxed{679 \text{ feet}}$$
This is the distance from point A to point B along the shore.
Distance Boat Lighthouse 2B30D2
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