1. **State the problem:** A robin flies 21 km at a bearing of 039° from its starting point, then flies 36 km due south. We need to find how far south of its starting point the robin is now, rounded to 1 decimal place. 2. **Analyze the first leg of the flight:** The robin flies 21 km at a bearing of 039°. Bearing is measured clockwise from north, so the robin's first leg has a north and east component. 3. **Calculate the north and east components of the first leg:** - North component = $21 \times \cos 39^\circ$ - East component = $21 \times \sin 39^\circ$ Using approximate values: - $\cos 39^\circ \approx 0.7771$ - $\sin 39^\circ \approx 0.6293$ So, - North component = $21 \times 0.7771 = 16.3191$ km - East component = $21 \times 0.6293 = 13.2153$ km 4. **Calculate the total south displacement:** The robin then flies 36 km due south. Since it initially moved north by 16.3191 km, the net south displacement from the start is: $$36 - 16.3191 = 19.6809$$ km south 5. **Round the answer:** To 1 decimal place, the robin is $19.7$ km south of its starting point. **Final answer:** The robin is 19.7 km south of its starting point.