Use an iron wire to form a rectangle whose width is length (4/9). If it is changed to form a square, the length must be shortened by 3.5cm. How long is this iron wire?
用一根铁丝，正好围成一个宽是长(4/9)的长方形，如果改围成一个正方形，必须将长缩短3.5cm，这根铁丝有多长？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(1/2) - (4/9)</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">3.5 / (1/18)</gadget>
<output>63</output>

<gadget id="calculator">63 * 4</gadget>
<output>252</output>

<result>252</result>