In a triangle, the median is a segment that connects a vertex to the midpoint of the opposite side, medians have the following properties:

-The triangle is divided by the median into two triangles having the same surface and all the other lines that divide the triangle into two parts of the same surface do not pass through the center of gravity

-The three medians of a triangle intersect at a point called the centroid or center of mass

- Each median lies two-thirds of its length between the vertex and the center of gravity, while the other third lies between the center of gravity and the midpoint of the opposite side.

ANGLES:

It has 3 internal angles, the sum of the internal angles equals a flat angle, ie 180 °

CLASSIFICATION OF TRIANGLES:

Triangles can be classified according to the relative length of the sides:

-In an equilateral triangle all sides have equal length. An equilateral triangle can be defined equivalently as an equiangular triangle, that is a triangle having its internal angles of equal width, equal to 60 °.

-In an isosceles triangle, two sides have equal length. An isosceles triangle can be defined equivalently as a triangle having two internal angles of equal width.

-In a scalene triangle, all sides have different lengths. A scalene triangle can be defined equivalently as a triangle having the three internal angles of different amplitudes.

-A right triangle has an internal angle of 90 °, that is, a right angle. The side opposite the right angle is called the hypotenuse; is the longest side of the right triangle. The other two sides of the triangle are called catheti. For this triangle the Pythagorean theorem holds.

-An obtuse triangle has an internal angle greater than 90 °, that is, an obtuse angle.

-An acute triangle has all internal angles less than 90 °, that is, it has three acute angles.

-An equiangular triangle, that is, if it has all internal angles equal, that is 60 °, that is, if and only if it is an equilateral triangle.