一个圆形花坛的直径是12米，这个花坛占地( )平方米，如果花坛的周围修一条2
\u4e00\u4e2a\u5706\u5f62\u82b1\u575b\u7684\u76f4\u5f84\u662f12\u7c73\uff0c\u8fd9\u4efd\u82b1\u575b\u5360\u5730\uff08\uff09\u5e73\u65b9\u7c73\uff0c\u5982\u679c\u82b1\u575b\u7684\u5468\u56f4\u4fee\u4e00\u67612\u7c73\u7684\u77f3\u5b50\u8def\uff0c\u8fd9\u6761\u8def\u9762\u79ef\uff08\uff09\u4f60\u597d\uff01
\u4e00\u4e2a\u5706\u5f62\u82b1\u575b\u7684\u76f4\u5f84\u662f12\u7c73\uff0c\u8fd9\u4efd\u82b1\u575b\u5360\u5730\uff08113.04\uff09\u5e73\u65b9\u7c73\uff0c\u5982\u679c\u82b1\u575b\u7684\u5468\u56f4\u4fee\u4e00\u67612\u7c73\u7684\u77f3\u5b50\u8def\uff0c\u8fd9\u6761\u8def\u9762\u79ef\uff0887.92\u5e73\u65b9\u7c73\uff09
3.14x(12\u00f72)²
=3.14x6²
=3.14x36
=113.04\u5e73\u65b9\u7c73
\u5185\u5706\u534a\u5f84\u662f12\u00f72=6\u7c73
\u5916\u5706\u534a\u5f846+2=8\u7c73
\u5c0f\u8def\u9762\u79ef\u662f\u2018
3.14x\uff088²-6²\uff09
=3.14x(64-36)
=3.14x28
=87.92\u7acb\u65b9\u7c73
\u5f88\u9ad8\u5174\u4e3a\u4f60\u89e3\u7b54\uff01\u5e0c\u671b\u80fd\u591f\u5e2e\u52a9\u5230\u4f60\u3002\u6709\u4e0d\u660e\u767d\u7684\u5730\u65b9\u8bf7\u8ffd\u95ee\uff0c\u6ee1\u610f\u8bf7\u91c7\u7eb3\u3002\u8c22\u8c22\uff01
\u5c31\u662f\u6c42\u5706\u73af\u7684\u9762\u79ef\u561b\uff0c\u5148\u7b97\u76f4\u5f84\u4e3a14\u7684\u5706\u7684\u9762\u79ef\uff0c\u518d\u7b97\u76f4\u5f8412\u7684\uff0c\u76f8\u51cf
花坛占地3.14*6*6=113.04平方米 路面积3.14*8*8-113.04=87.92绛旓細瀹冪殑鍛ㄩ暱=3.14脳12=37.68绫
绛旓細杩欎釜鍗婂渾褰㈣姳鍧涚殑闈㈢Н鏄56.52骞虫柟绫炽傝В锛氳鍗鍦嗗舰鑺卞潧鐨勭洿寰勬槸d绫炽3.14d梅2+d=30.84 2.57d=30.84 d=12 鎵浠ュ崐寰勪负锛12梅2=6锛堢背锛3.14x6²梅2 =3.14x36梅2 =56.52锛堝钩鏂圭背锛夌瓟锛氳繖涓崐鍦嗗舰鑺卞潧鐨勯潰绉槸56.52骞虫柟绫炽傘愯В鏋愩戞湰棰樿冩煡鍦嗙殑鐩稿叧鐭ヨ瘑銆傚凡鐭涓涓鍗婂渾褰㈣崏鍧紝瀹...
绛旓細鐭冲瓙璺鍥村渾鐨勭洿寰=12+2*2=16绫 鐭冲瓙璺殑闈㈢Н=鐭冲瓙璺鍥村渾鐨勯潰绉 - 鑺卞潧鐨勯潰绉 =蟺*16/2*16/2-蟺*12/2*12/2 =蟺*锛8*8-6*6锛=28蟺 =87.92骞虫柟绫
绛旓細浣犲ソ锛涓涓渾褰㈣姳鍧涚殑鐩村緞鏄12绫锛岃繖浠借姳鍧涘崰鍦帮紙113.04锛夊钩鏂圭背锛屽鏋滆姳鍧涚殑鍛ㄥ洿淇竴鏉2绫崇殑鐭冲瓙璺紝杩欐潯璺潰绉紙87.92骞虫柟绫筹級3.14x(12梅2)²=3.14x6²=3.14x36 =113.04骞虫柟绫 鍐呭渾鍗婂緞鏄12梅2=6绫 澶栧渾鍗婂緞6+2=8绫 灏忚矾闈㈢Н鏄3.14x锛8²-6²锛=3.14...
绛旓細鍛ㄩ暱鏄37.68绫
绛旓細12x3.14=37.68绫 绛旓細杩欎釜鑺卞潧鐨鍛ㄥ洿鎻掍笂绡辩瑔闇瑕佺绗37.68绫炽
绛旓細C=蟺d =3.14脳12 =37.68锛堢背锛
绛旓細瑙ｏ細鐭冲瓙璺渶澶栧緞鐨勫崐寰=12梅2+1=7绫 鐭冲瓙璺渶鍐呯粡鐨勫崐寰=12梅2=6绫 闈㈢Н=3.14脳7²-3.14脳6²=40.82骞虫柟绫 绛旓細鐭冲瓙璺潰绉槸40.82骞虫柟绫
绛旓細鐩村緞=12鍘樼背锛涘崐寰=12梅2=6鍘樼背锛涢潰绉=3.14脳6脳6=113.04骞虫柟鍘樼背锛涜閲囩撼 濡傛灉浣犺鍙垜鐨勫洖绛旓紝鏁鍙婃椂閲囩撼锛寏濡傛灉浣犺鍙垜鐨勫洖绛旓紝璇峰強鏃剁偣鍑汇愰噰绾充负婊℃剰鍥炵瓟銆戞寜閽 ~~鎵嬫満鎻愰棶鐨勬湅鍙嬪湪瀹㈡埛绔彸涓婅璇勪环鐐广愭弧鎰忋戝嵆鍙倊浣犵殑閲囩撼鏄垜鍓嶈繘鐨勫姩鍔 ~~O(鈭鈭)O锛岃寰楀ソ璇勫拰閲囩撼锛屼簰鐩稿府鍔 ...
绛旓細瑙ｏ細12梅2=6绫 6+1=7绫 3.14x7²-3.14x6²=3.14x13=40.82骞虫柟绫 绛旓細杩欐潯璺殑闈㈢Н鏄40.82骞虫柟绫炽
