Line segments are congruent if they have the same length. However, they need not be parallel. They can be at any angle or orientation on the plane. ... Rays and lines cannot be congruent because they do not have both end points defined, and so have no definite length.
Based on the information that they give you, prove "this". In your statements, you can use any of the properties of a triangle, then give the name of the property in your reasons.
