city plans to build a green avenue in three phases. After the first phase is completed, all the remaining works (14/19) are not completed. The ratio of the completed distance of the second phase to the third phase is 4:3. The third phase of the project is planned to be 9 kilometers long. How many kilometers long is this tree-lined avenue?
某城市计划分三期修建绿荫大道，第一期工程完工后，还剩全部工程的(14/19)没有完成，第二期工程完成的路程与第三期工程的比是4：3，第三期工程计划完成9公里，这条绿荫大道长多少公里？
<gadget id="calculator">14 / 19</gadget>
<output>14/19 = around 0.736842</output>

<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(14/19) * (3/7)</gadget>
<output>6/19 = around 0.315789</output>

<gadget id="calculator">9 / (6/19)</gadget>
<output>57/2 = around 28.5</output>

<result>57/2 = around 28.5</result>