A circular flower bed is drawn on paper with a scale of 1:400. The perimeter of this flower bed is 6.28 cm. Find the actual floor area of this flower bed.
一个圆形花坛，用1：400的比例尺画在纸上，这个花坛的周长是6.28厘米，求这个花坛的实际占地面积．
<gadget id="calculator">1 / 400</gadget>
<output>1/400 = around 0.0025</output>

<gadget id="calculator">6.28 / (1/400) / 100 / 3.14 / 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>

<result>50.24</result>