There are two rectangles of the same size, the length is 6 cm, and the width is 3 cm. Put these two rectangles together to form a square. What is the perimeter of the square?
有两个大小一样的长方形，长是6厘米，宽是3厘米，把这两个长方形拼成一个正方形，这个正方形的周长是多少厘米？
<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<result>24</result>