1. **State the problem:** Two fire-lookout stations A and B are 140 miles apart, with A directly south of B. The fire is spotted with bearings N55°E from A and S60°E from B. We need to find the distance from the fire to each station.
2. **Set up the coordinate system:** Place station B at the origin $(0,0)$ and station A at $(0,-140)$ since A is directly south of B.
3. **Find the coordinates of the fire:**
- From station A, bearing N55°E means the fire is located at an angle 55° east of north from A.
- From station B, bearing S60°E means the fire is located at an angle 60° east of south from B.
4. **Express the fire's coordinates from each station:**
Let the fire be at point $F=(x,y)$.
From A at $(0,-140)$:
$$x = d_A \sin 55^\circ$$
$$y = -140 + d_A \cos 55^\circ$$
where $d_A$ is the distance from A to the fire.
From B at $(0,0)$:
$$x = d_B \sin 60^\circ$$
$$y = -d_B \cos 60^\circ$$
where $d_B$ is the distance from B to the fire.
5. **Set the coordinates equal since both represent the same point $F$:**
$$d_A \sin 55^\circ = d_B \sin 60^\circ$$
$$-140 + d_A \cos 55^\circ = -d_B \cos 60^\circ$$
6. **Solve the system:**
From the first equation:
$$d_A = d_B \frac{\sin 60^\circ}{\sin 55^\circ}$$
Substitute into the second equation:
$$-140 + \left(d_B \frac{\sin 60^\circ}{\sin 55^\circ}\right) \cos 55^\circ = -d_B \cos 60^\circ$$
7. **Simplify:**
$$-140 + d_B \frac{\sin 60^\circ \cos 55^\circ}{\sin 55^\circ} = -d_B \cos 60^\circ$$
Bring all $d_B$ terms to one side:
$$-140 = -d_B \cos 60^\circ - d_B \frac{\sin 60^\circ \cos 55^\circ}{\sin 55^\circ}$$
$$-140 = -d_B \left( \cos 60^\circ + \frac{\sin 60^\circ \cos 55^\circ}{\sin 55^\circ} \right)$$
Multiply both sides by $-1$:
$$140 = d_B \left( \cos 60^\circ + \frac{\sin 60^\circ \cos 55^\circ}{\sin 55^\circ} \right)$$
8. **Calculate the trigonometric values:**
$$\sin 55^\circ \approx 0.8192$$
$$\cos 55^\circ \approx 0.5736$$
$$\sin 60^\circ \approx 0.8660$$
$$\cos 60^\circ = 0.5$$
9. **Evaluate the expression:**
$$\cos 60^\circ + \frac{\sin 60^\circ \cos 55^\circ}{\sin 55^\circ} = 0.5 + \frac{0.8660 \times 0.5736}{0.8192} = 0.5 + \frac{0.4967}{0.8192} = 0.5 + 0.6063 = 1.1063$$
10. **Find $d_B$:**
$$d_B = \frac{140}{1.1063} \approx 126.5$$ miles
11. **Find $d_A$:**
$$d_A = d_B \frac{\sin 60^\circ}{\sin 55^\circ} = 126.5 \times \frac{0.8660}{0.8192} = 126.5 \times 1.057 = 133.7$$ miles
**Final answer:**
- Distance from station A to fire: approximately $133.7$ miles
- Distance from station B to fire: approximately $126.5$ miles
Fire Distance 906293
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