If two rectangles with a length of 4 decimeters and a width of 2 decimeters are put together to form a square, what is the perimeter of the square?
把2个长为4分米，宽为2分米的长方形拼成一个正方形，正方形的周长是多少分米．
<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<result>16</result>