Make a cover for a water tank with a diameter of 0.75 meters. The diameter of the wooden cover is 0.05 meters larger than the diameter of the tank mouth. If a piece of iron is nailed around the edge of the wooden cover, how long is the iron piece?
给直径0.75米的水缸做一个盖，木盖的直径比缸口直径大0.05米，如果围着木盖的边沿钉一条铁片，铁片长多少厘米？
<gadget id="calculator">0.75 + 0.05</gadget>
<output>0.8</output>

<gadget id="calculator">3.14 * 0.8</gadget>
<output>2.512</output>

<result>2.512</result>