Concept — Teorema del coseno. Featured in chapters 29 · 33 Linked atoms 7 linked atoms. 29 Formule di addizione, duplicazione, bisezione Proof of the cosine subtraction formula 33 Trigonometria dei triangoli Angle from three sides Heron’s formula as a corollary Proof of the law of cosines Prove Heron’s formula Solving a triangle with the law of cosines The law of cosines