1. **Problem statement:** We are given a triangle ABC with sides AC = 130, side from C to the unlabeled vertex = 110, and an angle of 38° at the unlabeled vertex adjacent to the side of length 110. We need to find the angle $x$ at vertex C, which is opposite side AC.
2. **Identify known elements:**
- Side $AC = 130$
- Side adjacent to angle 38° (let's call it $BC$) = 110
- Angle at the unlabeled vertex (let's call it $B$) = 38°
- Angle at vertex $C$ is $x$ (unknown)
3. **Use the Law of Sines:**
The Law of Sines states:
$$\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}$$
where $a,b,c$ are sides opposite angles $A,B,C$ respectively.
4. **Assign sides and angles:**
- Side opposite angle $C$ is $AB$ (unknown length)
- Side opposite angle $B$ is $AC = 130$
- Side opposite angle $A$ is $BC = 110$
Since we know side $AC=130$ opposite angle $B=38^\circ$, and side $BC=110$ opposite angle $A$, we can find angle $A$ first:
$$\frac{110}{\sin A} = \frac{130}{\sin 38^\circ}$$
5. **Calculate $\sin A$:**
$$\sin A = \frac{110 \times \sin 38^\circ}{130}$$
Calculate $\sin 38^\circ \approx 0.6157$:
$$\sin A = \frac{110 \times 0.6157}{130} = \frac{67.727}{130} \approx 0.5217$$
6. **Find angle $A$:**
$$A = \arcsin(0.5217) \approx 31.4^\circ$$
7. **Find angle $x$ at vertex $C$:**
Sum of angles in triangle is $180^\circ$:
$$x = 180^\circ - 38^\circ - 31.4^\circ = 110.6^\circ$$
**Final answer:**
$$x \approx 110.6^\circ$$
Triangle Angle 1E988C
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