1. **State the problem:**
A goldfinch is flying 13 metres away from a bird box on top of a pole. The angle of depression from the goldfinch to the base of the pole is 32°. We need to find the distance between the goldfinch and the base of the pole.
2. **Understand the setup:**
The goldfinch, the base of the pole, and the bird box form a right triangle. The hypotenuse is the line from the goldfinch to the bird box (13 m). The angle of depression (32°) is the angle between the line of sight and the horizontal ground.
3. **Identify the sides:**
- Hypotenuse ($c$) = 13 m
- Angle of depression = 32°
- Distance from goldfinch to base of pole = adjacent side ($b$)
4. **Formula used:**
In a right triangle, cosine of an angle is adjacent over hypotenuse:
$$\cos(\theta) = \frac{\text{adjacent}}{\text{hypotenuse}}$$
5. **Apply the formula:**
$$\cos(32^\circ) = \frac{b}{13}$$
6. **Solve for $b$:**
$$b = 13 \times \cos(32^\circ)$$
7. **Calculate the value:**
$$b = 13 \times 0.8480 = 11.024$$
8. **Round to 2 decimal places:**
$$b \approx 11.02$$
**Final answer:** The distance between the goldfinch and the base of the pole is approximately **11.02 metres**.
Distance Goldfinch Pole Bf5043
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