Draw a circle with a compass, if the distance between the two feet of the compass is 3 cm, what is the area of the circle in square centimeters?
用圆规画一个圆，如果如果圆规两脚之间距离是3厘米，这个圆的面积是多少平方厘米．
<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<result>28.26</result>