Triangle Formulas
Area = 0.5 x base x height
Area (Heron) = sqrt(s(s-a)(s-b)(s-c)) where s = (a+b+c)/2
Area (SAS) = 0.5 x a x b x sin(C)
| Triangle Type | Definition |
|---|---|
| Equilateral | All 3 sides equal, all angles 60° |
| Isosceles | 2 sides equal, 2 angles equal |
| Scalene | All sides different |
| Right | One 90° angle, follows Pythagorean theorem |
Frequently Asked Questions
For a right triangle: a^2 + b^2 = c^2 where c is the hypotenuse (longest side). Example: sides 3 and 4 give hypotenuse sqrt(9+16) = sqrt(25) = 5. This is the 3-4-5 right triangle.
All interior angles of any triangle always add up to exactly 180 degrees. This is a fundamental theorem of Euclidean geometry.