The ratio of the upper base to the lower base of a right-angled trapezoid is 4:7. If the upper base is increased by 7 meters and the lower base is increased by 1 meter, it becomes a square. Find the area of the trapezoid.
一个直角梯形上底与下底的比是4：7，如果把上底增加7米，下底增加1米，就变成了一个正方形，求梯形的面积．
<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">7 - 4</gadget>
<output>3</output>

<gadget id="calculator">6 / 3</gadget>
<output>2</output>

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

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

<gadget id="calculator">8 + 14</gadget>
<output>22</output>

<gadget id="calculator">8 + 7</gadget>
<output>15</output>

<gadget id="calculator">15 / 2</gadget>
<output>15/2 = around 7.5</output>

<gadget id="calculator">22 * (15/2)</gadget>
<output>165</output>

<result>165</result>