Two identical rectangles are put together to form a square with side length 6 decimeters. What is the area of the original rectangle?
两个完全一样的长方形拼成一个边长6分米的正方形．原长方形的面积是多少平方分米？
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<result>18</result>