A piece of rectangular paper with a length of 31.4 cm and a width of 20 cm forms a cylinder, what is the lateral area of the cylinder in cm**2.
把一张长为31.4cm，宽为20cm的长方形纸围成一个圆柱，这个圆柱的侧面积是多少cm**2．
<gadget id="calculator">31.4 * 20</gadget>
<output>628</output>

<result>628</result>