If a rectangle with a length of 5 cm and a width of 3 cm is enlarged by 3:1, what is the area of the obtained figure in cm**2.
将一个长5cm，宽3cm的长方形按3：1放大，得到的图形的面积是多少cm**2．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">15 * 9</gadget>
<output>135</output>

<result>135</result>