If a rectangle is cut into two identical squares and the perimeter is increased by 6 cm, what is the area of the original rectangle in square centimeters?
把一个长方形剪成两个相同的正方形，周长增加6厘米，原来这个长方形的面积是多少平方厘米．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 * 3 * 2</gadget>
<output>18</output>

<result>18</result>