一个圆形花坛的半径是4米，沿着花坛的周围修一条宽1米的小路。小路的面积有多少平方米？
\u4e00\u4e2a\u5706\u5f62\u82b1\u575b\uff0c\u76f4\u5f84\u4e3a4\u7c73\uff0c\u6cbf\u82b1\u575b\u7684\u5468\u56f4\u4fee\u4e00\u67611\u7c73\u5bbd\u7684\u5c0f\u8def\uff0e\u8fd9\u6761\u5c0f\u8def\u7684\u9762\u79ef\u662f\u591a\u5c11\u5e73\u65b9\u7c73\u5185\u5706\u534a\u5f84\uff1a4\u00f72=2\uff08\u7c73\uff09\uff0c\u5916\u5706\u534a\u5f84\uff1a2+1=3\uff08\u7c73\uff09\uff0c3.14\u00d7\uff0832-22\uff09=3.14\u00d75=15.7\uff08\u5e73\u65b9\u7c73\uff09\uff0c\u7b54\uff1a\u8fd9\u6761\u5c0f\u8def\u7684\u9762\u79ef\u662f15.7\u5e73\u65b9\u7c73\uff0e
小路是一个环形，用两个圆的面积之差来计算，
S环形
=S大圆-S小圆
=πR²-πr²
=π(4+1)²-π*4²
=9π
≈28.26(平方米)
谢谢！
3.14*（4*4-1*1)
=3.14*15
=47.1(平方米)
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