On a rectangular iron plate with a length of 10 decimeters and a width of 6 decimeters, cut a piece of the largest circular iron plate. What is the area of this circular iron plate in square decimeters?
在一块长10分米、宽6分米的长方形铁板上，剪一块最大的圆形铁板，这块圆形铁板的面积是多少平方分米．
<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>

<result>28.26</result>