По теореме синусов:
$$\frac{BC}{\sin A} = \frac{AC}{\sin B}$$
$$AC = \frac{BC \cdot \sin B}{\sin A}$$
$$AC = \frac{11\sqrt{2} \cdot \sin 45°}{\sin 30°}$$
$$\sin 45° = \frac{\sqrt{2}}{2}$$
$$\sin 30° = \frac{1}{2}$$
$$AC = \frac{11\sqrt{2} \cdot \frac{\sqrt{2}}{2}}{\frac{1}{2}}$$
$$AC = 11\sqrt{2} \cdot \frac{\sqrt{2}}{2} \cdot 2 = 11 \cdot 2 = 22$$
Ответ: 22