What is the line of reflection that maps T(-4,5) U(8,2) V(-3,-7) onto T'(4,5) U'(-8,2) V'(3,-7)?

In the diagram, points d and e are marked by drawing arcs of equal size centered at b such that the arcs intersect ba and bc. then, intersecting arcs of equal size are drawn centered at points d and e. point p is located at the intersection of these arcs. based on this construction, m , and m