The circumference of a circle is 21.98cm, what is its area in cm**2.
一个圆的周长是21.98cm，它的面积是多少cm**2．
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">21.98 / 6.28</gadget>
<output>3.5</output>

<gadget id="calculator">3.5 ** 2</gadget>
<output>12.25</output>

<gadget id="calculator">3.14 * 12.25</gadget>
<output>38.465</output>

<result>38.465</result>