公园里有一个圆形花坛,直径是16米,在它周围修一条2米宽的环形便道,这条便道的面积是多少平方分米？
\u516c\u56ed\u91cc\u6709\u4e00\u4e2a\u5706\u5f62\u82b1\u575b,\u76f4\u5f84\u662f16\u7c73,\u5728\u5b83\u5468\u56f4\u4fee\u4e00\u67612\u7c73\u5bbd\u7684\u73af\u5f62\u4fbf\u9053\uff0c\u8fd9\u6761\u4fbf\u9053\u7684\u9762\u79ef\u662f\u591a\u5c11\u5e73\u65b9\u5206\u7c73\uff1f1\u3001\u76f4\u5f84\u662f16\u7c73\u7684\u5706\u5f62\u82b1\u575b,\u5728\u5b83\u5468\u56f4\u4fee\u4e00\u67612\u7c73\u5bbd\u7684\u73af\u5f62\u4fbf\u9053\uff0c\u76f8\u5f53\u4e8e2\u4e2a\u5706\u5708\uff0c\u4e00\u4e2a\u5927\u5706\uff08\u03a618),\u4e00\u4e2a\u5c0f\u5706\uff08\u03a618\uff09\uff0c\u7136\u540e\u6c42\u5b83\u4eec\u4e4b\u95f4\uff08\u5706\u73af\uff09\u7684\u9762\u79ef\u5dee\uff0c\u6839\u636e\u9898\u610f\u6709\uff1a
S\u5706\u73af=S\u5927\u5706-S\u5c0f\u5706
=3.14*18/2*18/2-3.14*16/2*16/2
=3.14*9*9-3.14*8*8
=3.14\uff089*9-8*8\uff09
=3.14*17
=53.38\u5e73\u65b9\u7c73=5338\u5e73\u65b9\u5206\u7c73
2\u3001\u5927\u5706\u7684\u5468\u957f=C\u5927\u5706=18*3.14\u7c73
\u6bcf\u96943.14\u7c73\u88c5\u4e0a\u4e00\u76cf\u5730\u706f\uff0c\u5219\u9700\u8981\u7684\u5730\u706f\u6570\u4e3a\uff1a C\u5927\u5706/3.14= 18*3.14 /3.14=18\u76cf
\u8fd9\u6761\u4fbf\u9053\u7684\u9762\u79ef\u662f5338\u5e73\u65b9\u5206\u7c73\uff1b\u4e00\u5171\u9700\u88c518\u76cf\u5730\u706f\u3002
\u82b1\u575b\u534a\u5f84\uff1a16/2=8\u7c73
\u5927\u5706\u534a\u5f84\uff1a8+2=10\u7c73
\u9762\u79ef\uff1a3.14x(10x10-8x8)=113.04\u5e73\u65b9\u7c73
3×[﹙16／2﹢2﹚²-﹙16／2﹚²]
=3×36
=108﹙平方分米﹚
绛旓細鎴戠殑 鍏洯閲屾湁涓涓渾褰㈣姳鍧,鐩村緞鏄16m,鍦ㄥ畠鐨勫懆鍥存湁涓鏉″1绫崇殑灏忚矾,閭ｄ箞,灏忚矾鐨勯潰绉槸澶氬皯骞虫柟绫? 鎴戞潵绛 1涓洖绛 #鐑# 鏌垮瓙鑴辨订鏂规硶鏈夊摢浜?鍖垮悕鐢ㄦ埛 2014-12-23 灞曞紑鍏ㄩ儴 鏈洖绛旇鎻愰棶鑰呴噰绾 宸茶禐杩 宸茶俯杩< 浣犲杩欎釜鍥炵瓟鐨勮瘎浠锋槸? 璇勮 鏀惰捣 鎺ㄨ崘寰嬪笀鏈嶅姟: 鑻ユ湭瑙ｅ喅鎮ㄧ殑闂,璇锋偍璇︾粏鎻忚堪...
绛旓細1銆鐩村緞鏄16绫崇殑鍦嗗舰鑺卞潧,鍦ㄥ畠鍛ㄥ洿淇竴鏉2绫冲鐨勭幆褰究閬,鐩稿綋浜2涓渾鍦,涓涓澶у渾(桅18),涓涓皬鍦(桅18),鐒跺悗姹傚畠浠箣闂(鍦嗙幆)鐨勯潰绉樊,鏍规嵁棰樻剰鏈:S鍦嗙幆=S澶у渾-S灏忓渾 =3.14*18/2*18/2-3.14*16/2*16/2 =3.14*9*9-3.14*8*8 =3.14(9*9-8*8) =3.14*17 =53.38骞虫柟绫=5338骞虫柟鍒嗙背2銆佸ぇ鍦...
绛旓細浣犲ソ锛氬鍦鐩村緞=16+2+2=20锛堢背锛夊杈圭紭鍛ㄩ暱=3.14脳20=62.8锛堢背锛夊畨瑁呭湴鐏暟=62.8梅5=12.56鈮13锛堢洀锛
绛旓細浣犲ソ锛侊紙16/2+2锛*2*蟺=62.8绫 62.8/5+1=13鐩忓湴鐏 鍏洯閲屾湁涓涓渾褰㈣姳鍧,鐩村緞鏄16绫,鍦ㄥ畠鐨勫懆鍥翠慨寤轰竴鏉′簩绫冲鐨勭幆褰㈣窇閬,娌跨幆褰㈣窇閬撶殑澶栬竟缂樻瘡闅斾簲绫宠涓鐩忓湴鐏紝涓鍏辫瀹夎13鐩忓湴鐏備粎浠ｈ〃涓汉瑙傜偣锛屼笉鍠滃嬁鍠凤紝璋㈣阿銆
绛旓細濡傚浘锛屽厛绠楀嚭璺戦亾鐨勫懆闀匡紝蟺鍙3.14锛屽璺戦亾鐩村緞涓20M锛屽懆闀夸负20蟺鈮62.8M锛62.8/5=12.54鈮12锛堢洀锛夊ソ鍍忓氨鏄繖鏍峰瓙锛岃涓嶅お娓呬簡...
绛旓細(1)16闄や互2绛変簬8 8鐨勫钩鏂圭瓑浜64 鑺卞潧闈㈢Н涓64涔樹互3.148鍔2绛変簬10 10鐨勫钩鏂圭瓑浜100 鑺卞潧鍔犱究閬撻潰绉负100涔樹互3.14缂栧闈㈢Н涓 100*3.14-64*3.14=锛100-64锛*3.14=36*3.14=113.04锛2锛113.04绾︾瓑浜100锛100闄や互5绛変簬20涓
绛旓細灏忚矾鐨勫鐩村緞16+2x2=20绫 鍛ㄩ暱鏄20x3.14=62.8绫 62.8梅5=12鐩忊︹2.8绫 12+1=13鐩
绛旓細鐭冲瓙璺鍥鍦嗙殑鐩村緞=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3.14脳18梅6.28=9
绛旓細鑺卞洯鍗婂緞8绫筹紝澶栫幆鍗婂緞8+2=10绫炽備究閬撻潰绉 = 蟺*(10*10) - 蟺*锛8*8锛=36蟺 绾︿负113.04 澶栫幆鍛ㄩ暱 = 2 * 蟺 *10 = 20蟺 鑳介渶瑕4蟺涓 绾︿负13涓
