Final answer:
Polygons with all equal side lengths are called equilateral polygons. An example is the square. This is a different concept than frequency polygons, which are a statistical tool for data representation.
Step-by-step explanation:
Polygons in which all sides have the same length are called equilateral polygons. An equilateral triangle is a simple example of such a polygon with three sides, where each side is equal in length. In more complex shapes like equilateral quadrilaterals, these are known as squares, where all sides are equal, and so are all angles.
It's important to differentiate this concept from frequency polygons. Frequency polygons are a type of graph used in statistics to show the distribution of a set of data. They are particularly useful in representing continuous data to make visual interpretation easier. Despite the similarity in the name, frequency polygons are not related to polygons with equal side lengths in geometry.