The new liquefied petroleum gas storage tank built by the gas company is an approximate cylinder with a height of 25 meters and a radius of the base of 20 meters. 2 meters outside the base, build a fence around the storage tank, what is the length of the fence?
煤气公司新建的液化石油气储存罐是一个近似的圆柱，高25米，底座半径是20米．在底座外2米处，绕着储存罐建造一圈护栏，护栏的长是多少米？
<gadget id="calculator">20 + 2</gadget>
<output>22</output>

<gadget id="calculator">3.14 * 22 * 2</gadget>
<output>138.16</output>

<result>138.16</result>