A parallelogram vegetable field has a base of 9 meters and a height twice that of the base. What is the area in square meters?
一块平行四边形的菜地，它的底是9米，高是底的2倍，面积是多少平方米．
<gadget id="calculator">9 * 2</gadget>
<output>18</output>

<gadget id="calculator">9 * 18</gadget>
<output>162</output>

<result>162</result>