If the 72 meters are distributed according to 1:3:5, what is the length of the middle part?
把72米按1：3：5分配，那么中间那部分的长是多少．
<gadget id="calculator">1 + 3 + 5</gadget>
<output>9</output>

<gadget id="calculator">3 / 9</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">72 * (1/3)</gadget>
<output>24</output>

<result>24</result>