The perimeter of a circular wooden board is 12.56m. If a layer of advertising paper is to be laid on the wooden board, what is the area of the advertising paper in m**2.
一块圆形木板的周长是12.56m，如果要在木板上铺一层广告纸，那么广告纸的面积是多少m**2．
<gadget id="calculator">12.56 / 3.14 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<result>12.56</result>