Triangle Formulas
Area Formulas
Base & Height: Area = ½ × b × h
Heron's Formula: Area = √[s(s−a)(s−b)(s−c)] where s = (a+b+c)/2
SAS: Area = ½ × a × b × sin(C)
Heron's Formula: Area = √[s(s−a)(s−b)(s−c)] where s = (a+b+c)/2
SAS: Area = ½ × a × b × sin(C)
Law of Cosines
c² = a² + b² − 2ab × cos(C)
Law of Sines
a/sin(A) = b/sin(B) = c/sin(C)
Pythagorean Theorem (Right Triangles)
a² + b² = c²
Triangle Types
| Type | Sides | Angles |
|---|---|---|
| Equilateral | All equal | All 60° |
| Isosceles | Two equal | Two equal base angles |
| Scalene | All different | All different |
| Right | Any | One angle = 90° |
| Obtuse | Any | One angle > 90° |