The circumference of a circle is 12.56dm, what is the area of the circle in dm**2.
一个圆的周长是12.56dm，这个圆的面积是多少dm**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>