Square paper with a side length of 6 decimeters forms a cylindrical paper tube (not counting the joints), what is the lateral area of the paper tube?
边长是6分米的正方形纸围成一个圆柱形纸筒(接头处不计)，这个纸筒的侧面积是多少．
<gadget id="calculator">6 * 6</gadget>
<output>36</output>

<result>36</result>