Plot elements on a circle with Ruby

application_helper.rb

  def angle_to_radians(angle)
    Math::PI * (angle * -1.0 / 180)
  end

  def radians_to_cartesian(radian, radius, offset_x, offset_y)
    {
      :x => (offset_x + (radius * Math::sin(radian))).round,
      :y => (offset_y + (radius * Math::cos(radian))).round
    }
  end

view.html.erb

<section>
  <%
    parts = [1,2,3,4,5,6]
    radius = 570/2
    offset_x = radius
    offset_y = radius
    degrees = 360/children.size
  %>

  <% parts.each_with_index do |child, i| %>
    <%
      radian = angle_to_radians(degrees * i);
      coords = radians_to_cartesian(radian, radius, offset_x, offset_y);
      style = "left: #{coords[:x]}px; bottom: #{coords[:y]}px; position: absolute;"
    %>

    <aside id="<%= (title = child.title.parameterize) %>" style="<%= style %>">
      <a href="#<%= title %>">
        <span><%= child.title %></span>
      </a>
    </aside>
  <% end %>
</div>
</section>