Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 4 - No. 1)
If two sides of a triangle and the included angle are given, which rule is most suitable for finding the third side?
Sine Rule
Cosine Rule
Pythagorean Theorem
Angle Sum Property
Explanation
The Cosine Rule is used when you have two sides and the included angle of a triangle.