A triangle is a polygon with three edges and three vertices.

An equilateral triangle has all sides the same length. An equilateral triangle is also a regular polygon with all angles measuring 60°

A scalene triangle has all its sides of different lengths. Equivalently, it has all angles of different measure. A right triangle is also a scalene triangle if and only if it is not isosceles.

Hatch marks also called tick marks, are used in diagrams of triangles and other geometric figures to identify sides of equal lengths