| M5 Home Page |
| Fact Monster | Triangles |
| Interactive Mathematics | Triangles |
| Interactive Mathematics | Angle Sum of a Triangle |
| Interactive Mathematics | Exterior Angle of a Triangle |
| Pink Monkey | Triangles |
| Purplemath | Basic Triangle Values |
| Math Reference | Congruent Triangles |
| Pink Monkey | Perimeter and Area: Triangle |
| Math Reference | Isosceles and Equilateral Triangles |
| Math Lair | The Pythagorean Theorem |
| Purplemath | The Distance Formula |
| Coolmath | Interior Angles |
| Coolmath | What Does Congruent Mean? |
| Purplemath | Geometric Formulae Review |
| Cut the Knot | Pythagorean Theorem |
| Cut the Knot | Morley's Miracle |
| AAA Math | Area of a Triangle |
| MathGuide | Quizmaster: Area of a Triangle |
| MathGuide | Quizmaster: Finding the Hypotenuse |
| MathGuide | Quizmaster: Finding the Leg |
| AAA Math | Geometry |
| Quia | Geometric Terms |
| Quia | Triangles and Polygons |