Use a 42 cm long rope to form a rectangle so that the ratio of its length to width is 4:3. What is the area of this rectangle in square centimeters?
用42厘米长的绳子围成一个长方形，使它的长和宽的比是4：3．这个长方形的面积是多少平方厘米？
<gadget id="calculator">42 / 2</gadget>
<output>21</output>

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

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

<gadget id="calculator">21 * (4/7)</gadget>
<output>12</output>

<gadget id="calculator">21 - 12</gadget>
<output>9</output>

<gadget id="calculator">12 * 9</gadget>
<output>108</output>

<result>108</result>