Xiao Ming walked around a circular flower bed twice at a speed of 31.4 meters per minute, which took exactly 5 minutes. What is the area of this flower bed in square meters?
小明以每分钟31.4米的速度绕一个圆形花坛步行2圈，正好用了5分钟．这个花坛的面积是多少平方米．
<gadget id="calculator">31.4 * 5</gadget>
<output>157</output>

<gadget id="calculator">157 / 2</gadget>
<output>157/2 = around 78.5</output>

<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">(157/2) / 6.28</gadget>
<output>12.5</output>

<gadget id="calculator">12.5 ** 2</gadget>
<output>156.25</output>

<gadget id="calculator">3.14 * 156.25</gadget>
<output>490.625</output>

<result>490.625</result>