Points.rb

class Point
  attr_reader :x, :y
  def initialize(x, y)
    @x = x
    @y = y
  end
  def to_s
   "(#{@x}, #{@y})"
  end
end

def distance(p1, p2)
  sum_of_squares = (p1.x - p2.x) ** 2 + (p1.y - p2.y) ** 2
  Math.sqrt(sum_of_squares.abs)
end

def average_distance(p1, p2, p3)
  distances = [distance(p1, p2), distance(p2, p3), distance(p1, p3)]
  distances.reduce(:+).to_f / distances.size
end

#testing...
p1 = Point.new(0, 0)
p2 = Point.new(0, 1)
p3 = Point.new(0, 2)

avg_distance = average_distance(p1, p2, p3)

puts "Points: [#{p1}, #{p2}, #{p3}]"
puts "the average distance is #{avg_distance}"