1. **State the problem:** We want to find the height of the cliff using the given triangle with angles and side lengths.
2. **Given data:**
- Angle at C: $72^\circ$
- Angle at B: $58^\circ$
- Side BA (opposite angle C): $18.4$ m
3. **Find angle A:**
$$
A = 180^\circ - 72^\circ - 58^\circ = 50^\circ
$$
4. **Use the Law of Sines:**
$$
\frac{BC}{\sin A} = \frac{BA}{\sin C}
$$
5. **Substitute known values:**
$$
\frac{BC}{\sin 50^\circ} = \frac{18.4}{\sin 72^\circ}
$$
6. **Solve for BC:**
$$
BC = \frac{18.4 \times \sin 50^\circ}{\sin 72^\circ}
$$
Calculate intermediate values:
$$
\sin 50^\circ \approx 0.7660, \quad \sin 72^\circ \approx 0.9511
$$
$$
BC = \frac{18.4 \times 0.7660}{0.9511} \approx \frac{14.0944}{0.9511} \approx 14.82 \text{ m}
$$
7. **Find the height (altitude) using angle B:**
Height $h = BC \times \sin 58^\circ$
$$
\sin 58^\circ \approx 0.8480
$$
$$
h = 14.82 \times 0.8480 \approx 12.57 \text{ m}
$$
8. **Conclusion:** The height of the cliff is approximately $12.6$ meters, not $17.7$ meters.
**Explanation:** Your approach was mostly correct in using the Law of Sines and sine functions, but the angle values and side used for BC calculation were slightly off, leading to a different height. Make sure to correctly identify all angles and sides before applying the Law of Sines.
Cliff Height 773A9D
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