What is the area of a parallelogram whose base is 3.5 cm long and twice its height?
一个平行四边形的底长3.5厘米，高是它的2倍，它的面积是多少．
<gadget id="calculator">3.5 * 2</gadget>
<output>7</output>

<gadget id="calculator">3.5 * 7</gadget>
<output>24.5</output>

<result>24.5</result>