Sometimes we can quickly spot objects with the same shape and match their "like parts," while at other times it can be surprisingly challenging!

Polygons are made of line segments and donâ€™t have any curves, so all we need to know to describe their shape is how their side lengths and their angles compare. Triangles are the simplest polygons and we need even less information to completely describe their shape. To determine how wide or narrow a triangle is or whether some of its sides have the same length, we only need to know how large its angles are.