Every triangle has three sides. The sides allow us to classify the different types of triangles according to their size.
For example, a triangle with two equal sides (edges) is an isosceles triangle and one in which all its sides (edges) are equal is an equilateral triangle. While a triangle that has all its sides different is an equilateral triangle.
![A1 - Sides of a triangle](/_ipx/f_png,s_500x499/https://cdn.tutorela.com/images/A1_-_Sides_of_a_triangle.width-500.png)