Answer
SAS
Work Step by Step
We see that only one pair of sides is marked as congruent. However, the triangles have at least one more congruent side, for they share a common side. Also, the straight line at the bottom of the triangle creates a linear pair between the 90 degree angle and the adjacent angle. Since 180-90=90, we see that the adjacent angle is also 90 degrees due to the definition of a linear pair. Thus, the triangles are congruent by SAS.
