Balloon Height E011A4
1. **Problem statement:** A balloon is observed from two stations, X and Y, which are 300 meters apart. At station X, the horizontal angle between the balloon and point C is $75^\circ 25'$ and the angle of elevation to the balloon is $18^\circ$. At station Y, the horizontal angle between the balloon and station X is $64^\circ 30'$. We need to find the height of the balloon.
2. **Understanding the problem:** We have a triangle formed by stations X, Y, and the balloon. The distance between X and Y is 300 m. We know some angles and want to find the vertical height of the balloon.
3. **Convert angles to decimal degrees:**
- $75^\circ 25' = 75 + \frac{25}{60} = 75.4167^\circ$
- $64^\circ 30' = 64 + \frac{30}{60} = 64.5^\circ$
4. **Use the Law of Sines to find distances:**
Let $B$ be the balloon, $X$ and $Y$ the stations.
- The horizontal angle at $X$ between balloon and $C$ is $75.4167^\circ$.
- The horizontal angle at $Y$ between balloon and $X$ is $64.5^\circ$.
Since $X$ and $Y$ are 300 m apart, the angle at $B$ is:
$$180^\circ - 75.4167^\circ - 64.5^\circ = 40.0833^\circ$$
5. **Apply Law of Sines:**
$$\frac{XY}{\sin(\angle B)} = \frac{XB}{\sin(\angle Y)} = \frac{YB}{\sin(\angle X)}$$
Given $XY = 300$ m, $\angle B = 40.0833^\circ$, $\angle X = 75.4167^\circ$, $\angle Y = 64.5^\circ$.
Calculate $XB$:
$$XB = \frac{XY \times \sin(\angle Y)}{\sin(\angle B)} = \frac{300 \times \sin(64.5^\circ)}{\sin(40.0833^\circ)}$$
Calculate values:
- $\sin(64.5^\circ) \approx 0.9004$
- $\sin(40.0833^\circ) \approx 0.6441$
So,
$$XB = \frac{300 \times 0.9004}{0.6441} \approx 419.3 \text{ m}$$
6. **Find height using angle of elevation at X:**
Angle of elevation $= 18^\circ$.
Height $h = XB \times \tan(18^\circ)$
Calculate $\tan(18^\circ) \approx 0.3249$
So,
$$h = 419.3 \times 0.3249 \approx 136.2 \text{ m}$$
**Final answer:** The height of the balloon is approximately **136.2 meters**.