Segment WT and DG are congruent which means that the shape and size, but we are allowed to flip, slide or turn. In this example the shapes are congruent (you only need to flip one over and move it a little). Angles are congruent when they are the same size (in degrees or radians). Sides are congruent when they are the same length.
Depends it could be 14812 if they want total value or just the interest would be 7812