A cylindrical tin can has a base radius of 5 cm and a height of 18 cm. Now it is necessary to paste a circle of trademark paper on its side (not counting the pasted part), what is the minimum area of this paper?
一种圆柱形铁皮罐，底面半径是5cm，高是18cm．现要给它侧面贴一圈商标纸(粘贴部分不计)，这张纸的面积至少有多大？
<gadget id="calculator">3.14 * 5 * 2 * 18</gadget>
<output>565.2</output>

<result>565.2</result>