If the farm wants to surround the largest circular cattle pen with wire on a square grass field with a side length of 60 meters, how many meters of wire is needed?
农场要在一块边长是60米的正方形草地上用铁丝围一个最大的圆形牛栏，需要铁丝多少米？
<gadget id="calculator">60 * 3.14</gadget>
<output>188.4</output>

<result>188.4</result>