The upper base of a right-angled trapezoid is 10 decimeters. If the upper base is extended by 4 decimeters, it becomes a square. What is the area of the trapezoid in square decimeters?
一个直角梯形的上底是10分米，如果把上底延长4分米，就变成一个正方形，这个梯形的面积是多少平方分米．
<gadget id="calculator">10 + 4</gadget>
<output>14</output>

<gadget id="calculator">10 + 14</gadget>
<output>24</output>

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<gadget id="calculator">24 * 7</gadget>
<output>168</output>

<result>168</result>