If the upper base of a right-angled trapezoid is extended by 3 cm, it becomes a square with a side length of 8 cm. What is the area of the trapezoid in square centimeters?
一个直角梯形上底延长3厘米后，就成了边长是8厘米的正方形，这个梯形的面积是多少平方厘米．
<gadget id="calculator">8 - 3</gadget>
<output>5</output>

<gadget id="calculator">5 + 8</gadget>
<output>13</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">13 * 4</gadget>
<output>52</output>

<result>52</result>