По теореме синусов: $$\frac{BC}{sin A} = 2R$$ $$R = \frac{BC}{2sin A}$$ $$R = \frac{6\sqrt{2}}{2sin 45°}$$ $$R = \frac{6\sqrt{2}}{2 \cdot \frac{\sqrt{2}}{2}}$$ $$R = \frac{6\sqrt{2}}{\sqrt{2}}$$ $$R = 6$$
Ответ: 6