一个圆形沿半径剪开并拼出一个长方形,已知这个长方形的周长是20.7cm,求圆的面积 将一个圆沿半径剪开，再拼成一个近似的长方形，已知这个长方形的...
\u4e00\u4e2a\u5706\u5f62\u6cbf\u534a\u5f84\u526a\u5f00\u5e76\u62fc\u51fa\u4e00\u4e2a\u957f\u65b9\u5f62,\u5df2\u77e5\u8fd9\u4e2a\u957f\u65b9\u5f62\u7684\u5468\u957f\u662f20.7cm,\u6c42\u5706\u7684\u9762\u79ef\u534a\u5f8420.7\u00f72\u00f7\uff083.14+1\uff09
=10.35\u00f74.14
=2.5\u5398\u7c73
\u9762\u79ef3.14\u00d72.5\u00d72.5=19.625\u5e73\u65b9\u5398\u7c73
\u8fd9\u4e2a\u9898\u6709\u610f\u601d\u3002\u957f\u65b9\u5f62\u7684\u5bbd\u662f\u534a\u5f84\uff0c\u957f\u662f\u534a\u5468\u957f
\u8bbe\u534a\u5f84 x \u53d6 pai = 3.14
\uff08x+3.14x\uff09* 2 = 82.8
\u7684x = 10
\u9762\u79ef 3.14 * 10 * 10 = 314 CM2 \u8fd9\u5c31\u662f\u5706\u7684\u9762\u79ef
\u5468\u957f\u662f 2* 3.14 * 10 = 62.8cm
4.14r=10.35
r=2.5
面积:2.5²×3.14=19.625
绛旓細鍗婂緞鏄3 鍛ㄩ暱鏄6*3.14=18.84鍘樼背 闈㈢Н鏄3.14*9=28.26骞虫柟鍘樼背 锛堟彁绀猴細闀挎柟褰㈠懆闀挎瘮鍦嗗舰鍛ㄩ暱澶2涓崐寰勶紝鎵浠涓涓崐寰鏄3鍘樼背锛屾牴鎹叕寮忓彲姹傚嚭鍛ㄩ暱涓庨潰绉級
绛旓細鎷兼帴闀挎柟褰紝閭ｄ箞灏辨槸鍓鎴愪竴涓釜鐨勫皬鎵囧舰鎷兼帴鍚э紒閭ｄ箞璋鍦嗙殑鍗婂緞涓簉锛岄偅涔堥暱鏂瑰舰鐨勫灏辨槸r锛岃鍏堕暱涓篵 鍒欐湁鍏紡 2r+2b=2蟺r+8 鑰岄暱鏂瑰舰鐨勯暱涔嬪拰 鎭版伆灏辨槸鍦嗙殑鍛ㄩ暱锛屽嵆: 2蟺r =2b 涔熷氨鏄 闀挎柟褰㈠懆闀挎瘮鍦嗗懆闀挎墍闀跨殑8鍘樼背锛屾鏄鍑虹殑闀挎柟褰㈢殑涓や釜瀹戒箣鍜岋紝涔熷氨鏄渾鐨勫崐寰勭殑2鍊...
绛旓細鎶涓涓渾褰绾哥墖娌跨潃瀹冪殑鍗婂緞骞冲潎鍒嗘垚鑻ュ共鍒嗗悗鍓紑锛岀敤瀹冧滑鎷兼垚涓涓繎浼奸暱鏂瑰舰銆傝繖涓暱鏂瑰舰鐨勫懆灏濊瘯16.56鍘樼背锛岄暱鏂瑰舰鐨勫涓庡渾褰㈢焊鐗囩殑鍗婂緞鐩哥瓑銆傝繖涓渾褰㈢焊鐗囩殑闈㈢Н鏄紙 12.56 锛夊钩鏂瑰帢绫筹紵
绛旓細杩欎釜棰樼殑姝ｈВ搴旇鐢ㄥ井绉垎鏉ヨВ锛屼絾鑰冭檻瀹為檯搴旇鏄垵涓殑闈㈢Н杞崲鐨勯鐩鍦嗗舰绾哥墖鍓紑锛屾兂鎷兼垚闀挎柟褰紝灏辫鍓緢澶氬緢澶氱墖锛岃秺澶鎷煎嚭鏉灏辫秺鎺ヨ繎闀挎柟褰傚亣璁句负鏃犵┓澶氱墖锛屽垯锛氭牴鎹渾鐨勯潰绉28.26锛屽彲寰鍦嗙殑鍗婂緞涓3骞虫柟绫炽傚渾褰㈡敼涓洪暱鏂瑰舰鍚庨潰绉笉鍙橈紝鍒欓暱鏂瑰舰闈㈢Н涔熶负28.26骞虫柟绫筹紝鍗婂緞涓哄锛屽垯闀夸负9....
绛旓細12.56骞虫柟鍘樼背 鎶涓涓渾褰绾哥墖鍓紑鍚庯紝鎷兼垚涓涓绛変簬鍗婂緞銆侀潰绉笉鍙樼殑杩戜技闀挎柟褰紟杩欎釜杩戜技闀挎柟褰㈢殑闀垮氨鏄渾鍛ㄩ暱鐨勪竴鍗婏紝姹鍑哄渾鐨勫崐寰锛屾牴鎹渾闈㈢Н鍏紡姹傚嚭鍦嗙殑闈㈢Н銆傚崐寰=12.56梅3.14梅2=2鍘樼背锛涢暱=12.56梅2=6.28鍘樼背锛涢潰绉=2脳6.28=12.56骞虫柟鍘樼背 ...
绛旓細鏈绠鍗曟濊冿紝鏍规嵁棰樻剰鐭ワ細闀挎柟褰㈢殑鍛ㄩ暱姣斿渾鐨勫懆闀垮2cm銆傚皢鍦嗘部鍗婂緞鍒嗗紑锛屾嫾鎴愯繎浼奸暱鏂瑰舰銆傝锛鍦嗙殑鍗婂緞鏄疪锛屾墍浠ラ暱鏂瑰舰鐨勫灏辨槸R锛岄暱鏂瑰舰鐨勯暱鍙互鐢ㄏR鏉ヨ〃绀恒傚垯锛2R+2蟺R-2蟺R=2cm锛岃В寰桼=1cm 鍒欏渾鐨勯潰绉疭=蟺R^2=蟺銆
绛旓細闈㈢Н涓25*蟺骞虫柟鍘樼背
绛旓細鍥犱负鎵鎷兼垚鐨勯暱鏂瑰舰鐨勫懆闀=鍥懆闀+鍥洿寰勶紝鍥犱负鍥懆闀垮20鍘樼背锛屾墍浠ュ鍑烘潵鐨20鍘樼背灏辨槸鍥殑鐩村緞锛屾墍浠ュ洯鐨鍗婂緞涓20/2=10鍘樼背銆傚渾闈㈢Н=3.14*10*10=314骞虫柟鍘樼背銆
绛旓細24.84梅2=12.42鍘樼背 闀夸笌瀹界殑鍜岋紝涔熸槸鍗婂緞鍜屽渾鍛ㄩ暱鐨勪竴鍗婄殑鍜 12.42梅锛1+3.14锛=3鍘樼背 杩欐槸鍗婂緞 鍦嗙殑闈㈢Н锛3.14脳3²=28.26骞虫柟鍘樼背
绛旓細銆愮瓟妗堛50.24骞虫柟鍘樼背 銆愯В鏋愩戣繎浼奸暱鏂瑰舰鐨勫懆闀挎瘮鍦嗙殑鍛ㄩ暱澶鍑烘潵鐨勬槸2鏉″崐寰勶紝鎵浠ワ紝鍦嗙殑鍗婂緞涓 8梅2=4(鍘樼背)鍦嗙殑闈㈢Н涓 3.14脳4脳4=50.24(骞虫柟鍘樼背)
