a + b + c
¡î(s(s-a)(s-b)(s-c))
Cosine Rule
The area of a triangle can be calculated using Heron's formula. It uses the three side lengths of the triangle.
Triangle angles can be calculated using the Law of Cosines. The sum of all triangle angles equals 180¡Æ.
Use Heron's formula which calculates triangle area using side lengths.
The sum of interior angles of a triangle is always 180 degrees.