Triangle Math: Formulas & Congruency Rules
Solving a triangle means finding all missing side lengths and interior angles. To uniquely solve a triangle, you must know at least three parameters, and at least one of these parameters must be a side length.
Solving Rules by Case
1. Side-Side-Side (SSS)
When three sides (a, b, c) are known, the angles are solved using the **Law of Cosines**:
2. Side-Angle-Side (SAS)
When two sides and their included angle are known, solve for the third side using the Law of Cosines. Then, resolve the remaining angles using the Law of Sines.
3. Law of Sines
For ASA, AAS, and SSA cases, we rely on the **Law of Sines**: