The perimeter of a rectangle is 24 cm, the ratio of length to width is 7:5, what is the area?
长方形的周长是24厘米，长和宽的比是7：5，面积是多少．
<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<gadget id="calculator">7 + 5</gadget>
<output>12</output>

<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">12 * (7/12)</gadget>
<output>7</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">12 * (7/12) * 12 * (5/12)</gadget>
<output>35</output>

<result>35</result>