Question

Complete the following statement:

Two line segments are congruent if ___.

Answer 1

Two line segments are congruent if they have the same length.
For example:

Here $AB$ is a line segment where the starting point is $A$ and the end point is $B$. And the length of $AB$ is $5cm$. Similarly, $CD$ is a line segment where the starting point is $C$ and the end point is $D$. The length of the $CD$ is also $5cm$. Both the line segments have the same length. That means both line segments are equal.
Hence, they are congruent to each other.