If the width of a rectangle is increased by 4 meters and the length remains the same, then it becomes a square and its area is increased by 48 square meters. What is the perimeter of this rectangle in meters?
一个长方形的宽如果增加4米，长不变，那么它就变成一个正方形，并且面积增加48平方米，这个长方形的周长是多少米．
<gadget id="calculator">48 / 4</gadget>
<output>12</output>

<gadget id="calculator">12 - 4</gadget>
<output>8</output>

<gadget id="calculator">12 + 8</gadget>
<output>20</output>

<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<result>40</result>