A cylinder is surrounded by a rectangular cardboard with a length of 20 cm and a width of 12 cm. What is the lateral area of the cylinder in square centimeters?
用一张长20厘米、宽12厘米的长方形纸板围成一个圆柱，这个圆柱的侧面积是多少平方厘米？
<gadget id="calculator">20 * 12</gadget>
<output>240</output>

<result>240</result>