After subtracting 4 centimeters from the length of a rectangle, its area is reduced by 24 square centimeters, and what is left is a square. What is the area of this square?
一个长方形的长去掉4厘米后，它的面积就减少24平方厘米，剩下的是正方形，这个正方形的面积是多少．
<gadget id="calculator">24 / 4</gadget>
<output>6</output>

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

<result>36</result>