There are two identical rectangles with a length of 6 cm and a width of 3 cm, put them together to form a square. What is the perimeter of this square in centimeters
有两个同样的长方形，长都是6厘米，宽都是3厘米，把它拼成一个正方形．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>