The length of a rectangle is 2.8 meters and twice the width, what is the area of the rectangle?
一个长方形的长是2.8米，是宽的2倍，这个长方形的面积是多少．
<gadget id="calculator">2.8 / 2</gadget>
<output>1.4</output>

<gadget id="calculator">2.8 * 1.4</gadget>
<output>3.92</output>

<result>3.92</result>