Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 3 - No. 42)
If you are given the lengths of all three sides (a, b, and c) of a triangle, what can you directly calculate using the Cosine Rule?
The angles of the triangle.
The area of the triangle
The perimeter of the triangle
The length of the largest side.
Explanation
You can calculate the angles.