1. **Problem statement:** Find the unknown side $x$ in triangle e) with sides 6.553 cm, 4 cm, and $x$, and angles 30°, 25°, and 125°.
2. **Formula:** Use the sine rule for sides:
$$\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}$$
where $a,b,c$ are sides opposite angles $A,B,C$ respectively.
3. **Identify known values:**
- Side opposite 30° is 6.553 cm
- Side opposite 25° is 4 cm
- Side opposite 125° is $x$
4. **Apply sine rule to find $x$:**
$$\frac{x}{\sin 125^\circ} = \frac{6.553}{\sin 30^\circ}$$
5. **Rearrange to solve for $x$:**
$$x = \frac{6.553}{\sin 30^\circ} \times \sin 125^\circ$$
6. **Calculate values:**
- $\sin 30^\circ = 0.5$
- $\sin 125^\circ = \sin (180^\circ - 125^\circ) = \sin 55^\circ \approx 0.8192$
7. **Substitute and compute:**
$$x = \frac{6.553}{0.5} \times 0.8192 = 13.106 \times 0.8192 = 10.74$$
8. **Final answer:**
The length of side $x$ is approximately **10.7 cm** (to 3 significant figures).
Sine Rule Side Ffabaf
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