The perimeter of a rectangle is 84 cm, and the ratio of length to width is 3:4. What is the area of the rectangle in square centimeters?
一个长方形的周长是84cm，长和宽的比是3：4，这个长方形的面积是多少平方厘米？
<gadget id="calculator">84 / 2</gadget>
<output>42</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">42 * (3/7)</gadget>
<output>18</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">42 * (4/7)</gadget>
<output>24</output>

<gadget id="calculator">18 * 24</gadget>
<output>432</output>

<result>432</result>