There is a rectangle, if its length is removed by 5 centimeters, the area will be reduced by 20 square centimeters, and the remaining part is just a square. What is the area of this rectangle in square centimeters?
有一个长方形，把它的长去掉5厘米，面积就减少20平方厘米，剩下的部分正好是个正方形，这个长方形的面积是多少平方厘米．
<gadget id="calculator">20 / 5</gadget>
<output>4</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">16 + 20</gadget>
<output>36</output>

<result>36</result>