A square iron plate, draw the largest circle on it, the known circumference of the circle is 18.84 decimeters. What is the area of this iron plate in square decimeters?
一块正方形铁板，在上面画一个最大的圆，已知圆的周长是18.84分米．这块铁板的面积是多少平方分米？
<gadget id="calculator">18.84 / 3.14</gadget>
<output>6</output>

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

<result>36</result>