             four_thirds_pi
              </p>
            </td>
<td>
              <p>
                4/3 π
              </p>
            </td>
<td>
              <p>
                4.18879
              </p>
            </td>
<td>
              <p>
                <a href="http://en.wikipedia.org/wiki/Sphere#Volume_of_a_sphere" target="_top">volume
                of a sphere</a> = 4/3 π r³
              </p>
            </td>
</tr>
<tr>
<td>
              <p>
                one_div_two_pi
        