For a right-angled trapezoid, if the upper base is extended by 5 cm, the area will increase by 20 cm2, which is exactly a square. What is the area of the original trapezoid in square centimeters?
一个直角梯形，上底如果延长5厘米，面积增加20平方厘米，这样正好是一个正方形．原来梯形的面积是多少平方厘米．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">20 * (2/5)</gadget>
<output>8</output>

<gadget id="calculator">8 * 8</gadget>
<output>64</output>

<gadget id="calculator">64 - 20</gadget>
<output>44</output>

<result>44</result>