For a triangular vegetable field, its base is 140 meters and twice its height. What is the area of this triangular vegetable field in square meters?
一个三角形的菜地，它的底是140米，是高的2倍，这个三角形的菜地面积是多少平方米？
<gadget id="calculator">140 / 2</gadget>
<output>70</output>

<gadget id="calculator">70 / 2</gadget>
<output>35</output>

<gadget id="calculator">140 * 35</gadget>
<output>4_900</output>

<result>4_900</result>