Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 1 - No. 2)
In a triangle, if you know the lengths of two sides and the included angle, which rule would you likely use to find the length of the third side?
Sine Rule
Cosine Rule
Pythagorean Theorem
Angle Sum Property
Paliwanag
The Cosine Rule is used to find side lengths when two sides and an included angle are known.