Find the largest circle in a rectangle with a length of 18 cm and a width of 12 cm. Find the area of this circle.
长18厘米、宽12cm的长方形中有一个最大的圆，求此圆的面积．
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">3.14 * 36</gadget>
<output>113.04</output>

<result>113.04</result>