The side length of a square is equal to the radius of the circle, the area of the square is 20m**2, what is the area of the circle in meters**2.
一个正方形的边长和圆的半径相等，正方形的面积是20米**2，圆的面积是多少米**2．
<gadget id="calculator">20 * 3.14</gadget>
<output>62.8</output>

<result>62.8</result>