1. Найдите BC

Дано:

• \[ \triangle ABC \]
• \[ \angle C = 90^{\circ} \]
• \[ \angle A = 60^{\circ} \]
• \[ AB = 10 \]

Решение:

1. \[ \angle B = 180^{\circ} - 90^{\circ} - 60^{\circ} = 30^{\circ} \]
2. \[ BC = AB \cdot \cos(60^{\circ}) = 10 \cdot \frac{1}{2} = 5 \]
3. \[ BC = AB \cdot \sin(30^{\circ}) = 10 \cdot \frac{1}{2} = 5 \]

Ответ: 5