The types of triangles are **differentiated by the size of their sides and by the measure of their internal angles** . Remember that the triangle is a polygon with three sides, connected by its three vertices that form three angles.

Types of triangles | Triangle Name | Characteristic |
---|---|---|

According to the size of its sides | Isosceles | Two sides of equal size. |

Equilateral | All three sides are equal in size. | |

Scalene | The three sides have different measurements. | |

According to their angles | Acute angle | All three angles measure less than 90º . |

Obtuse angle | One of the angles measures more than 90º . | |

Rectangle | One of the angles measures 90º . |

Index

## Types of triangles according to their sides

A triangle is a three-sided polygon. Depending on the measure and the relationship of the sides to each other, we have different types of triangles:

**Isosceles triangle**: has two sides of equal size.**Equilateral triangle**: the three sides measure the same and therefore the three angles are equal.**Scalene triangle**: its three sides have different measurements.

## 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, the triangles can be:

**Acute 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 triangle**: one of the angles is an obtuse angle, that is, greater than 90º.

You may also be interested in seeing Types of angles .