After combining three squares of the same size into a rectangle, the perimeter of the rectangle is 20 cm less than the sum of the perimeters of the original three squares, what is the area of each original square in square centimeters?
把大小一样的三个正方形拼成一个长方形后，长方形的周长比原来三个正方形的周长之和少20厘米，则原来每个正方形的面积应是多少平方厘米．
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<result>25</result>