cylinder is formed by a piece of paper with a length of 10 cm and a width of 8 cm. What is its lateral area?
用一张长10厘米，宽8厘米的纸围成一个圆柱，它的侧面积是多少．
<gadget id="calculator">10 * 8</gadget>
<output>80</output>

<result>80</result>