一个圆环它的直径是五厘米半径是三厘米它的面积和周长是多少？ 一个圆，它的半径是三厘米，求它的周长和面积
\u4e00\u4e2a\u5706\u7684\u534a\u5f84\u662f5\u5398\u7c73\uff0c\u5b83\u7684\u76f4\u5f84\u662f( )\uff0c\u5468\u957f\u662f( )\uff0c\u9762\u79ef\u662f( )\u3002\u4e00\u4e2a\u5706\u7684\u534a\u5f84\u662f5\u5398\u7c73\uff0c\u5b83\u7684\u76f4\u5f84\u662f(5\u00d72=10 )\uff0c\u5468\u957f\u662f(2\u03c0r=2\u00d7\u03c0\u00d75=10\u03c0)\uff0c\u9762\u79ef\u662f( \u03c0r^2=\u03c05^2=25\u03c0)\u3002
\u4eb2\uff0c\u5982\u6709\u5e2e\u52a9\uff0c\u8bf7\u91c7\u7eb3\uff01\uff01\uff01~\(\u2267\u25bd\u2266)/~
\u56e0\u4e3a\u60a8\u7684\u91c7\u7eb3\uff0c\u6211\u4eec\u624d\u6709\u66f4\u591a\u52a8\u529b\u5e2e\u52a9\u66f4\u591a\u7684\u4eba\u3002
\u795d\u60a8\u5b66\u4e60\u5de5\u4f5c\u751f\u6d3b\u987a\u5fc3\u5982\u610f\uff01\uff01\uff01\u5bb6\u5ead\u548c\u8c10\u7f8e\u6ee1\u5e78\u798f\uff01\uff01\uff01\uff01
\u4e00\u4e2a\u5706\uff0c\u5b83\u7684\u534a\u5f84\u662f\u4e09\u5398\u7c73\uff0c\u6c42\u5b83\u7684\u5468\u957f\u548c\u9762\u79ef
\u5706\u5468\u957f\uff1a3.14\u00d73\u00d72=18.84\u5398\u7c73
\u9762\u79ef\uff1a3.14\u00d73²=28.26\u5e73\u65b9\u5398\u7c73
\u4f9b\u53c2\u8003
面积：（3×3-2.5×2.5）×3.14=2.75×3.14=8.635平方厘米
内环周长：5×3.14=15.7厘米
外环周长：3×2×3.14=18.84厘米
圆环直径是五厘米，半径应该是二点五厘米。你写的半径是三厘米，是抄错了吧。
绛旓細闈㈢Н锛氾紙3脳3-2.5脳2.5锛壝3.14=2.75脳3.14=8.635骞虫柟鍘樼背 鍐呯幆鍛ㄩ暱锛5脳3.14=15.7鍘樼背 澶栫幆鍛ㄩ暱锛3脳2脳3.14=18.84鍘樼背
绛旓細浣犲ソ锛鍦嗙幆闈㈢Н=澶栧渾闈㈢Н-鍐呭渾闈㈢Н 澶栧渾闈㈢Н=3.14脳5²=78.5锛堝钩鏂鍘樼背锛夊唴鍦嗛潰绉=3.14脳3²=28.26锛堝钩鏂瑰帢绫筹級鍦嗙幆闈㈢Н=78.5-28.26=50.24锛堝钩鏂瑰帢绫筹級涔熷彲浠ヨ繖鏍风畻锛3.14脳锛5²-3²锛=3.14脳16 =50.24锛堝钩鏂瑰帢绫筹級
绛旓細=93.415骞虫柟鍘樼背
绛旓細鍦ㄤ竴涓渾鐜腑澶栧渾鐨勭洿寰勬槸浜斿帢绫,鍐呭渾鐨勫崐寰勬槸涓ゅ帢绫,鐜澶氬皯鍘樼背?5梅2-2 =2.5-2 =0.5鍘樼背
绛旓細浠鍗婂緞2.5鍘樼背鐢诲渾濡備笅鍥撅紝鍗涓虹洿寰勬槸5鍘樼背鐨勫渾锛
绛旓細杩欎釜鐜舰鐨闈㈢Н=蟺脳5²-蟺脳2.5²=18.75蟺 =58.9骞虫柟鍘樼背
绛旓細涓涓幆褰鐨勫鍦嗗崐寰勫拰鍐呭渾鐩村緞閮芥槸5cm,杩欎釜鐜舰鐨勯潰绉 鏄紙 锛夊钩鏂筩m 鍐呭渾鍗婂緞涓5/2=2.5 鎵浠 闈㈢Н=蟺*(5^2-2.5^2)=3.14*18.75=58.875(骞虫柟鍘樼背)
绛旓細鍗婂緞=2.5鍘樼背 楂=3鍘樼背 琛ㄩ潰绉 =2脳搴曢潰绉+渚ч潰绉 =2脳3.14脳2.5脳2.5+2脳3.14脳2.5脳3 =86.35骞虫柟鍘樼背 浣撶Н =搴曢潰绉楅珮 =3.14脳2.5脳2.5脳3 =58.875绔嬫柟鍘樼背
绛旓細鎴戜滑鐭ラ亾鍦鐨勭洿寰勬槸5鍘樼背锛屾墍浠ユ垜浠彲浠ヤ娇鐢ㄤ笂闈㈢殑鍏紡鏉ヨ绠楀懆闀垮拰鍗婂緞銆侰1=蟺脳5锛宺=d/2銆傚浜庣浜屼釜闂锛氭垜浠煡閬撳渾鐨勫懆闀挎槸12.5鍘樼背锛屾墍浠ユ垜浠彲浠ヤ娇鐢ㄤ笂闈㈢殑鍏紡鏉ヨ绠楃洿寰勩侱2=C2/蟺銆傜幇鍦ㄦ垜浠紑濮嬭绠椼傜涓涓闂鐨勭瓟妗堟槸锛氱洿寰勪负5鍘樼背鐨勫渾锛屽渾瑙勪袱瑙掍箣闂寸殑璺濈鏄2.5鍘樼背銆傜浜屼釜闂鐨...
绛旓細鍒╃敤鍦嗙殑鍛ㄩ暱璁＄畻鍏紡鍟 2蟺r 涔熷氨鏄鐩村緞涔樹互蟺灏卞彲浠ュ緱鍒板懆闀 5脳3.14=15.7cm銆傜煡閬撳懆闀28.26锛屾眰鍑哄崐寰勶紝2蟺r=28.26 鍙互姹傚嚭r=4.5 鐒跺悗鐢ㄥ渾瑙勭敾鍗婂緞涓4.5鐨勫渾灏辫浜嗐
