rectangle with a length of 5 cm and a width of 3 cm is enlarged by 4:1 to obtain the area of the figure in cm**2.
一个长5cm、宽3cm的长方形，按4：1放大后得到的图形的面积是多少cm**2．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<gadget id="calculator">20 * 12</gadget>
<output>240</output>

<result>240</result>