If the upper base of a trapezoid is extended by 5 cm, the area increases by 25 cm2 and becomes a parallelogram. If the upper base of the original trapezoid is 10 cm, find the area of the original trapezoid.
一个梯形若上底延长5厘米，面积就增加25平方厘米，并且变成了一个平行四边形．如果原来这个梯形的上底是10厘米，求原来梯形的面积．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">25 * (2/5)</gadget>
<output>10</output>

<gadget id="calculator">10 + 10 + 5</gadget>
<output>25</output>

<gadget id="calculator">2 / 5 / 2</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">25 * 25 * (1/5)</gadget>
<output>125</output>

<result>125</result>