The area of an isosceles trapezoid is 54 square centimeters, the upper base is 5 cm, and the lower base is 13 cm. To cut a circle with the largest area in this isosceles trapezoid. What is the remaining area of the trapezoid?
等腰梯形的面积是54平方厘米，上底是5厘米，下底是13厘米．若要在这个等腰梯形内剪下一个面积最大的圆．这个梯形剩下的面积多大？
<gadget id="calculator">5 + 13</gadget>
<output>18</output>

<gadget id="calculator">2 / 18</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">54 * (1/9)</gadget>
<output>6</output>

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

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<gadget id="calculator">54 - 28.26</gadget>
<output>25.74</output>

<result>25.74</result>