A road has been built for 4.5 kilometers, which is the remaining 45%. How long is this road in kilometers?
一条路，已经修了4.5千米，是剩下的45%，这条路长多少千米．
<gadget id="calculator">20 + 9</gadget>
<output>29</output>

<gadget id="calculator">9 / 29</gadget>
<output>9/29 = around 0.310345</output>

<gadget id="calculator">4.5 / (9/29)</gadget>
<output>14.5</output>

<result>14.5</result>