Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 6 - No. 32)
If a triangle has sides a=4, b=5, and c=6. What formula can be used to find the angle opposite the side with the value of 6?
cos C = (a² + b² - c²) / 2ab
cos C = (c² + b² - a²) / 2bc
cos C = (a² + c² - b²) / 2ac
Law of Sines
Giải thích
The Cosine rule.