The types of triangles are differ by the size of their sides and by the measure of their internal angles.. Recall that the triangle is a polygon with three sides, connected by its three vertices that form three angles.
| Types of triangles | Triangle Name | Feature |
|---|---|---|
| According to the size of its sides | Isosceles | Two sides of equal size. |
| Equilateral | The three sides are of equal size. | |
| Scalene | The three sides have different measures. | |
| According to their angles | Acutangle | The three angles measure less than 90º. |
| Obtuse-angle | One of the angles measures more than 90º.. | |
| Rectangle | One of the angles measures 90º.. |
Types of triangles according to their sides
A triangle is a polygon with three sides. According to the measure and the relation of the sides to each other, we have different types of triangles:
- Isosceles triangle: it has two sides of equal measure.
- Equilateral triangle: the three sides measure the same and, therefore, the three angles are equal.
- Scalene triangle: its three sides have different measures.
Types of triangles according to their angles
A triangle has three internal angles, which in total add up to 180º. According to the measure of the angles, triangles can be:
- Acute-angled triangle: the three angles measure less than 90º, that is, they are acute angles.
- Right triangle: one of the angles of the triangle measures 90º, that is, it is a right angle.
- Obtuse-angled triangle: one of the angles is an obtuse angle, that is, greater than 90º.
You may be interested to see also Types of angles.
