## Elementary Geometry for College Students (5th Edition)

$\overline{MP}$ is the pair of parts that are congruent by Identity.
The pair of parts that are congruent by Identity is the side or the angle that both triangles have as its own side or angle. In this image, we can see that both triangles have $\overline{MP}$ as a side of its own. Therefore, here $\overline{MP}$ is the pair of parts that are congruent by Identity.