Find the proportional solution: x: 3.2 = (1/5): (5/4).
求比例解：x：3.2=(1/5)：(5/4)．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3.2 * (1/5)</gadget>
<output>0.64</output>

<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">0.64 / (5/4)</gadget>
<output>0.512</output>

<result>0.512</result>