Build a cylindrical digester with a bottom radius of 2 meters and a depth of 1 meter. Spread cement around the pool, what is the area of the cemented part in square meters (π takes 3.14)
砌一个圆柱形沼气池，底面半径是2米，深是1米．在池的周围抹上水泥，抹水泥部分的面积是多少平方米(π取3.14)
<gadget id="calculator">3.14 * 2 * 2 * 1</gadget>
<output>12.56</output>

<result>12.56</result>