Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 3 - No. 27)
Which rule is best when you know two sides and the included angle of a non-right triangle and want to find the length of the third side?
Law of Sines
Pythagorean theorem
Cosine Rule
The area = 1/2absinC rule
설명
The Cosine Rule.