Solution: Calculate Shape Area

class Shape
  
end
class Triangle < Shape
  attr_accessor :base, :height
  
  def initialize(base, height)
    @base = base
    @height = height
  end
  
  def area
    return base * height / 2.0
  end
  
end
class Rectangle <  Shape
  
  attr_accessor :width, :length
  
  def initialize(length, width)
    @length = length
    @width = width
  end
  
  def area
    return length * width
  end
  
end
class Square < Rectangle 
  def initialize(length)
    super(length, length)
  end
end
puts Triangle.new(10, 5).area()
puts Rectangle.new(10, 5).area()
puts Square.new(10).area()