如下图，正方形BEFG的边长为7米，正方形ABCD的边长为5米，求阴影部分的面积。 下图正方形BEFG的边长为7米，正方形ABCD的边长为5米，...
\u5982\u4e0b\u56fe\uff0c\u6b63\u65b9\u5f62BEFG\u8fb9\u957f\u4e3a7\u7c73\uff0c\u6b63\u65b9\u5f62ABCD\u7684\u8fb9\u957f\u4e3a5\u7c73\uff0c\u6c42\u9634\u5f71\u90e8\u5206\u7684\u9762\u79ef\u3002\u4e0a\u9762\u4e24\u4e2a\u7a7a\u767d\u4e09\u89d2\u5f62\u9762\u79ef\u5206\u522b\u4e3a0.5*5*5=12.5\u548c0.5*7*\uff087-5\uff09=7\uff0c\u4e0b\u9762\u7a7a\u767d\u4e09\u89d2\u5f62\u9762\u79ef\u662f0.5*7*\uff085+7\uff09=42
\u9634\u5f71\u5904\u9762\u79ef\u4e3a5*5+7*7-12.5-7-42=12.5
7\u00d77+5\u00d75-5\u00d75\u00f72-7\u00d7\uff087+5\uff09\u00f72-7\u00d7\uff087-5\uff09\u00f72
\uff1d74-12.5-42-7\uff1d12.5
Sgfc=1/2x7x2=7平方米
Scfeb=7x7-7=42平方米
Safe=1/2x7x12=42平方米
所以阴影面积
42+12.5-42＝12.5平方米
阴影部分的面积=S（ABCD）+S（EFGH）-S（△CDA）-S（△AEF）-S（△FGC）
=5²+7²-1/2x5x5-1/2x7x（7+5）-1/2x7x（7-5）
=25+49-25/2-49
=25/2
7*7+5*5-（7+5）*7/2-5*5/2-7*(7-5)/2
=49+25-42-12.5-7
=12.5
绛旓細鍒嗘瀽锛氭眰闃村奖閮ㄥ垎鐨勯潰绉紝鍗虫眰涓夎褰笁瑙掑舰ACF鐨勯潰绉 鑰屼笁瑙掑舰ACF鏄釜閽濊涓夎褰紝閭ｄ箞 涓夎褰CF闈㈢Н=澶х殑姝ｆ柟褰㈢殑杈归暱*灏忕殑姝ｆ柟褰㈣竟闀 闃村奖閮ㄥ垎闈㈢Н=7*5*1/2=17.5锛堝钩鏂圭背锛夈愬悓瀛︼紝鐪嬫噦鍚楋紵銆戙愭偍鐨勫ソ璇勬槸瀵规垜鐨勮偗瀹氾紝璋㈣阿~銆
绛旓細42+12.5-42锛12.5骞虫柟绫
绛旓細鎼炰釜鍥剧湅鐪嬪搰
绛旓細锛74-12.5-42-7锛12.5
绛旓細涓婇潰涓や釜绌虹櫧涓夎褰㈤潰绉垎鍒负0.5*5*5=12.5鍜0.5*7*锛7-5锛=7锛屼笅闈㈢┖鐧戒笁瑙掑舰闈㈢Н鏄0.5*7*锛5+7锛=42 闃村奖澶勯潰绉负5*5+7*7-12.5-7-42=12.5
绛旓細姝ｆ柟褰EFG鐨勮竟闀夸负3.5锛孲闃村奖=3.5脳3.5=12.25锛屾晠绛旀涓猴細12.25銆傚瑙掔嚎鐩哥瓑涓斾簰鐩稿瀭鐩村钩鍒嗙殑鍥涜竟褰㈡槸姝ｆ柟褰備竴缁勯偦杈圭浉绛夛紝鏈変笁涓鏄洿瑙掔殑鍥涜竟褰㈡槸姝ｆ柟褰傛棦鏄彵褰㈠張鏄煩褰㈢殑鍥涜竟褰㈡槸姝ｆ柟褰傚垽瀹氬畾鐞嗭細1锛氬瑙掔嚎鐩哥瓑鐨勮彵褰㈡槸姝ｆ柟褰2锛氭湁涓涓涓虹洿瑙掔殑鑿卞舰鏄鏂瑰舰銆3锛氬瑙掔嚎浜掔浉...
绛旓細瑙ｏ細濡傚浘锛岃繛DB锛孏E锛孎K锛屽垯DB鈭E鈭K锛屽湪姊舰GDBE涓紝S鈻矴DB=S鈻矱DB锛堝悓搴曠瓑楂橈級锛屸埓S鈻矴DB-S鈻矪DM=S鈻矱DB-S鈻矪DM锛屸埓S鈻矰GE=S鈻矴EB锛屽悓鐞哠鈻矴KE=S鈻矴FE锛庘埓S闃村奖=S鈻矰GE+S鈻矴KE锛=S鈻矴EB+S鈻矴EF锛=S姝ｆ柟褰GBEF锛=4脳4 =16 ...
绛旓細濡傚浘锛岃繛BD銆丟E銆丗K锛屽垯DB 鈭 GE 鈭 FK锛 鍦ㄦ褰BEG涓紝S 鈻矴ED =S 鈻矴EB 锛 鍚岀悊鍙緱锛孲 鈻矴EK =S 鈻矴EF 锛 鈭碨 闃村奖 =S 鈻矴ED +S 鈻矴EK 锛 =S 鈻矴EB +S 鈻矴EF 锛 =S 姝ｆ柟褰EFG 锛 鈭姝ｆ柟褰EFG鐨勮竟闀夸负b锛 鈭碨 闃村奖 =b 2 锛 鏁呯瓟妗堜负锛歜 2 锛
绛旓細S钃濓紳S榛戙係榛勶紳S绾 鈭碨鈯緿EK锛漇榛+S绾紳3²锛9
绛旓細瑙ｏ細锛1锛夊鍥锯憼锛岃姝ｆ柟褰EFG鐨勮竟闀夸负x锛屽垯BE=FG=BG=x 鈭礎B=3锛孊C=6锛屸埓AG=AB锕G=3锕锛屸埖GF鈭E锛屸埓鈻矨GF鈭解柍ABC锛屸埓锛屽嵆锛岃В寰楋細x=2锛屽嵆BE=2 锛2锛夊瓨鍦ㄦ弧瓒虫潯浠剁殑t锛岀悊鐢憋細濡傚浘鈶★紝杩囩偣D浣淒H鈯C浜嶩锛屽垯BH=AD=2锛孌H=AB=3锛岀敱棰樻剰寰楋細BB鈥=HE=t锛孒B鈥=|t锕2|锛孍C...
