square with a side length of 3 cm is enlarged by 5:1, what is the area of the obtained figure?
一个边长3厘米正方形按5：1放大，得到的图形的面积是多少．
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">15 * 15</gadget>
<output>225</output>

<result>225</result>