For a trapezoid, if the lower base is shortened by 3 cm, the area is reduced by 6 cm2 and becomes a parallelogram. Given that the upper base of the trapezoid is 10 cm, find the area of the original trapezoid.
一个梯形，若下底缩短3厘米，面积就减少6平方厘米，并且变成了一个平行四边形．已知梯形的上底是10厘米，求原梯形的面积．
<gadget id="calculator">10 + 3 + 10</gadget>
<output>23</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">6 * (2/3)</gadget>
<output>4</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">23 * 2</gadget>
<output>46</output>

<result>46</result>