The island shown at right has two post offices. The postal service wants
to divide the island into two zones so
that anyone within each one is always
closer to their own post office than to
the other one. Copy the island and
the locations of the post offices and
locate the dividing line between the
two zones. Explain how you know this
dividing line solves the problem. Or pick
several points in each one and make
sure they are closer to that zone's post
office than they are to the other one.