If a rectangle with a length of 1 cm and a width of 2 cm is enlarged by 3:1, what is the area of the enlarged rectangle in square centimeters?
把一个长1厘米、宽2厘米的长方形按3：1放大，放大后的长方形的面积是多少平方厘米．
<gadget id="calculator">1 * 3 * 2 * 1 * 3</gadget>
<output>18</output>

<result>18</result>