The upper base of the trapezoid is increased by 3 cm, and the lower base is increased by 2.5 cm to form a square with a perimeter of 36 cm. Find the area of the trapezoid.
梯形的上底增加3厘米，下底增加2.5厘米后就成了一个周长为36厘米的正方形，求梯形的面积．
<gadget id="calculator">36 / 4</gadget>
<output>9</output>

<gadget id="calculator">9 - 3</gadget>
<output>6</output>

<gadget id="calculator">9 - 2.5</gadget>
<output>6.5</output>

<gadget id="calculator">6 + 6.5</gadget>
<output>12.5</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">12.5 * (9/2)</gadget>
<output>56.25</output>

<result>56.25</result>