Cut out a largest circle from a square of cardboard and measure the circumference of the circle to be 62.8 cm. What is the circumference of the square in cm?
一个正方形纸板，剪出一个最大的圆，测得此圆周长为62.8cm，则正方形的周长是多少cm．
<gadget id="calculator">62.8 / 3.14</gadget>
<output>20</output>

<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<result>80</result>