If the length of a rectangle is subtracted by 4 centimeters, it becomes a square and its area is reduced by 24 square centimeters. What is the area of this square in square centimeters?
一个长方形的长减去4厘米后变成一个正方形，面积减少了24平方厘米，这个正方形的面积是多少平方厘米．
<gadget id="calculator">24 / 4</gadget>
<output>6</output>

<gadget id="calculator">6 * 6</gadget>
<output>36</output>

<result>36</result>