The Federal Communications Commission (FCC) monitors radio stations to make sure that their signals do not interfere with each other. They prevent interference by assigning appropriate frequencies to each station. Suppose six stations are located at the distances shown in the table below (in miles), and two stations cannot use the same channel when they are within 150 miles of each other. Use a graph model to determine how many different frequencies are needed for these six stations. Be sure to describe what the vertices and edges represent, and what

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