If the radius of a circle is 1 cm, if it is increased by 2 cm, how many cm will the circumference increase?
一个圆的半径是1厘米，增加2厘米，周长增加多少厘米？
<gadget id="calculator">3.14 * 2 * 2</gadget>
<output>12.56</output>

<result>12.56</result>