Most of the ways we have described lines so far involve where the lines "sit" in relation to each other. Another type of relationship is more about the shape and size of the lines segments. In this area, segments are like any other shape. For example, compare the shapes in the two photos below. What can you say about them? Click each image to compare your own ideas to ours.

In the language of geometry, the hearts in the first image are congruent They are EXACTLY the same size and same shape. The shoes are not congruent because, although they have the same shape, they are not the same size.

One way to remember the meaning of congruent is to think about identical twins. Unlike fraternal twins, identical twins tend to look exactly the same to people who don't know them well. Congruent shapes are like identical twins in shape and size. To decide if two objects are congruent, ask yourself if they are identical in size and shape.