A square has the same perimeter as a circle. If the radius of the circle is 20 cm, what is the side length of the square in cm?
一个正方形与一个圆形的周长相等，如果圆的半径是20厘米，正方形的边长是多少厘米？
<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * 20 * (1/2)</gadget>
<output>31.4</output>

<result>31.4</result>