A rectangular vegetable field is surrounded by a fence with a length of 140m. The ratio of the length to the width of the rectangle is 4:3. What is the area of this vegetable field?
一块长方形的菜地，周围篱笆长140m，长方形的长与宽的比是4：3，这块菜地的面积是多少？
<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">(4/7) / 2</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">140 * (2/7)</gadget>
<output>40</output>

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

<gadget id="calculator">(3/7) / 2</gadget>
<output>3/14 = around 0.214286</output>

<gadget id="calculator">140 * (3/14)</gadget>
<output>30</output>

<gadget id="calculator">40 * 30</gadget>
<output>1_200</output>

<result>1_200</result>