Use a piece of rectangular paper with a length of 6.28 decimeters and a width of 2 decimeters to form a cylindrical paper tube. What is its lateral area?
用一张长6.28分米，宽2分米的长方形纸，围成一个圆柱形纸筒，它的侧面积是多少．
<gadget id="calculator">6.28 * 2</gadget>
<output>12.56</output>

<result>12.56</result>