Congruent Squares

These squares are congruent.  You can tell because they have parallel lines which are cut by a transversal. It follows that the interior angles are congruent.  It also shows that the same-side interior angles are supplementary.  This is obvious to see because a square has four 90 degree angles.  The squares also share a side and the same parallel lines. In conclusion, these two squares are congruent. (~KM5)