There is a circular goldfish pond with a diameter of 10 meters in the Oriental Children's Park. A stainless steel guardrail is installed 0.5 meters outside the goldfish pond. How many meters is the length of the guardrail?
东方儿童公园有一个直径为10米的圆形金鱼池，在金鱼池外0.5米处要装一圈不锈钢护栏，这个护栏的长度要多少米？
<gadget id="calculator">10 + 0.5 + 0.5</gadget>
<output>11</output>

<gadget id="calculator">3.14 * 11</gadget>
<output>34.54</output>

<result>34.54</result>