The length of a rectangle is 7 meters and the width is 5 meters. If it is folded into the largest square, what is the perimeter of the square?
一个长方形的长是7米，宽是5米，把它折成一个最大的正方形，这个正方形的周长是多少米．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>