Uncle Li has a rectangular vegetable garden with a ratio of length to width of 4:3. Uncle Li built a 42-meter-long fence around the vegetable garden. Do you know how big Uncle Li's vegetable garden is?
李大伯有一个长方形菜园，长和宽的比为4：3．李大伯在菜园的四周围了一圈长42米的篱笆．你知道李大伯的菜园面积有多大吗？
<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">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">21 * (3/7)</gadget>
<output>9</output>

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

<result>108</result>