piece of rectangular paper with a length of 8 cm and a width of 5 cm is used to fold a largest square. What is the perimeter of this square in cm?
一张长方形的纸，长8厘米，宽5厘米，用它折一个最大的正方形，这个正方形的周长是多少厘米．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>