A circle is formed by an iron wire with a length of 18.84 decimeters. What is the area of the circle in square decimeters?
用一根长18.84分米的铁丝围成一个圆，这个圆的面积是多少平方分米．
<gadget id="calculator">18.84 / 3.14 / 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>