Question: Adrian leaves Darwin and flies $357$ km due south. He then turns and flies on a bearing of $N29^\circ W$ until he is due west of Darwin. How far (to the nearest km) is Adrian from Darwin now?
1. **State the problem:** Adrian flies $357$ km due south from Darwin, then flies on a bearing of $N29^\circ W$ until he is due west of Darwin. We need to find how far Adrian is from Darwin now.
2. **Understand the scenario:**
- First leg: $357$ km south.
- Second leg: flies on bearing $N29^\circ W$ until directly west of Darwin.
3. **Set up coordinate system:**
- Place Darwin at origin $(0,0)$.
- After first leg, Adrian is at point $A = (0, -357)$.
4. **Second leg direction:**
- Bearing $N29^\circ W$ means $29^\circ$ west of north.
- The direction vector has components:
$$x = -\sin 29^\circ, \quad y = \cos 29^\circ$$
5. **Let the distance flown on second leg be $d$ km.**
- Coordinates after second leg:
$$x = 0 + d(-\sin 29^\circ) = -d \sin 29^\circ$$
$$y = -357 + d \cos 29^\circ$$
6. **Condition: Adrian is due west of Darwin after second leg.**
- Being due west means $y=0$.
7. **Solve for $d$:**
$$0 = -357 + d \cos 29^\circ$$
$$d \cos 29^\circ = 357$$
$$d = \frac{357}{\cos 29^\circ}$$
8. **Calculate $d$: (using $\cos 29^\circ \approx 0.8746$)**
$$d \approx \frac{357}{0.8746} \approx 408.2 \text{ km}$$
9. **Find Adrian's final position coordinates:**
$$x = -d \sin 29^\circ \approx -408.2 \times 0.4848 = -197.9$$
$$y = 0$$
10. **Distance from Darwin now:**
- Since Adrian is at $(-197.9, 0)$, distance is $197.9$ km.
11. **Final answer:**
- To the nearest km, Adrian is $198$ km from Darwin now.