What is the area of the figure obtained by enlarging a rectangle with a length of 5 cm and a width of 3 cm at 4:1?
一个长5厘米、宽3厘米的长方形按4：1放大后得到的图形面积是多少．
<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>