Law of Cosines Calculator
Enter sides a and b and the included angle C to find side c.
The Law of Cosines relates the three sides of any triangle to one of its angles. It generalises the Pythagorean theorem: when the angle C = 90°, cos(C) = 0 and the formula reduces to a² + b² = c².
💡
Tip: Use the Law of Cosines when you know: (1) two sides and the included angle (SAS), or (2) all three sides (SSS). For other cases, use the Law of Sines.
🔒
100% 免费
无需注册
✓
准确
经过验证的公式
⚡
即时
即时结果
📱
移动友好
所有设备