The perimeter of a square is equal to the perimeter of a circle, and the side length of the square is 6.28 meters. What is the area of the circle in square meters?
一个正方形的周长和一个圆的周长相等，正方形的边长6.28米，圆的面积是多少平方米．
<gadget id="calculator">6.28 * 4</gadget>
<output>25.12</output>

<gadget id="calculator">25.12 / 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>