There is a circular street flower bed with a diameter of 8 meters. Now it is necessary to set up a fence around the flower bed 1 meter outside the flower bed. How many meters is this fence?
有一个圆形的街心花坛，直径是8米．现在要在花坛外1米的地方绕花坛设置一围栏，这个围栏长多少米？
<gadget id="calculator">8 + 1 + 1</gadget>
<output>10</output>

<gadget id="calculator">10 * 3.14</gadget>
<output>31.4</output>

<result>31.4</result>