Use two rectangles with a length of 50 cm and a width of 25 cm to form a square. What is the perimeter of this square?
用两个长50厘米，宽25厘米的长方形，拼成一个正方形．这个正方形的周长是多少？
<gadget id="calculator">50 * 4</gadget>
<output>200</output>

<result>200</result>