Answer
$\overline{PQ}$ is a common side.
Work Step by Step
Two triangles emerge from the diagram - one with points PQS and the other with points PQR.
Both triangles contain the points P and Q, which creates a pair of matching sides on each triangle.
Draw the two triangles separately if a visual aid is needed - each should look like an upside-down right triangle. Its does not matter where the points are named.
