The radius of a circular flower bed is 2 meters. Now it is necessary to expand the flower bed and double the radius. At this time, how many meters does the floor area of the flower bed increase**2.
一个圆形花坛的半径是2米，现在要扩建花坛，将半径扩大2倍，这时花坛的占地面积增加了多少米**2．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

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

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

<gadget id="calculator">50.24 - 12.56</gadget>
<output>37.68</output>

<result>37.68</result>