Triangles are geometric figures consisting of three sides and three angles. They are classified in several ways, but one of the most common classifications is according to the measure of their sides and the measure of their angles.

As for the classification by measure of sides, triangles can be equilateral (with three sides of equal length), isosceles (with two sides of equal length) or scalene (with three sides of different lengths).

On the other hand, according to the measure of their angles, triangles can be classified as acutangles (with three acute angles), rectangles (with a right angle) or obtuse angles (with an obtuse angle).

As for their origin, the classification and study of triangles has its origins in ancient civilizations, such as the Egyptian and Babylonian, where geometric concepts were used for the construction of monuments and for solving practical problems.