如图是横截面为梯形ABCD的水坝,坝顶宽AD=6米,坝高为4,斜坡AB的坡比i=1:1.2，斜坡DC的坡角为45°
\u6c34\u5e93\u5927\u575d\u7684\u6a2a\u5207\u9762\u662f\u68af\u5f62ABCD,\u575d\u9876DC=6m,\u575d\u9ad822m,\u659c\u5761AD\u7684\u5761\u6bd4\u4e3a1:3\uff0c\u659c\u5761BC\u7684\u5761\u6bd4\u4e3a1\uff1a2.5.\u6c42\u659c\u5761AD\u7684\u5761\u89d2\u901a\u5e38\u628a\u5761\u9762\u7684\u5782\u76f4\u9ad8\u5ea6h\u548c\u6c34\u5e73\u5bbd\u5ea6l\u7684\u6bd4\u53eb\u505a\u5761\u6bd4
\u6839\u636e\u9898\u610f\u53ef\u77e5\uff1aDE\uff1aAE=1\uff1a3 CF\uff1aBF=1\uff1a2.5 DE=CF=22 CD=EF=6
\u6240\u4ee5AE=22\u00d73=66 BF=22\u00d72.5=55
AB= AE+EF+BF=66+6+55=127\uff08m\uff09
AD\u7b49\u4e8eAE\u5e73\u65b9\u52a0DE\u5e73\u65b9\u548c\u518d\u5f00\u5e73\u65b9\u5f9769.6\uff08m\uff09
\u659c\u5761AD\u7684\u5761\u89d2=arctan1/3=18\u00b026\u2032
1\u3001\u2220B=60\u00b0,\u90a3\u4e48\u2220BAE=30\u00b0,\u6839\u636e\u4e09\u89d2\u5f6230\u5ea6\u89d2\u6240\u5bf9\u76f4\u89d2\u8fb9\u7b49\u4e8e\u659c\u8fb9\u7684\u4e00\u534a\u7684\u5b9a\u7406\uff0c\u53ef\u77e5AB=2BE
\u56e0\u4e3aBE²+AE²=AB²=(2BE)²,\u5373BE²+18²=4BE²,\u53ef\u5f97BE=6\u221a3
2\u3001\u2220C=45\u00b0,\u6240\u4ee5FC=DF=18
3\u3001\u56e0\u4e3aEF=AD=8
\u6240\u4ee5BC=BE+EF+FC=6\u221a3+8+18=26+6\u221a3
\u5373\u575d\u5e95BC\u957f26+6\u221a3\u3002
绛旓細绗竴棰鏄14.4 绗簩棰樻槸绾︿负3.27
绛旓細鍒嗘瀽锛氾紙1锛夎繃C浣淐E鈯B涓嶦锛岀敱BC鐨勫潯搴﹀拰鍧濋珮鍙緱鍑築C鐨勯暱锛庯紙2锛塀C鐨勫潯搴︿负鍧¤鐨勬鍒囧硷紝鏍规嵁棰樹腑鐨勬潯浠跺彲姹傚嚭BC鐨勫潯搴︼紟锛3锛夎繃D浣淒F鈯B涓嶧锛屽垯AB=AF+FE+EB锛屾牴鎹鎰忔墍缁欐潯浠跺彲姹傚嚭AB鐨勯暱搴︼紟瑙ｏ細锛1锛夌敱棰樻剰寰桟E=DF=4.5锛宼anB=鈭3/3锛屸埓BC=5绫筹紝BE=4.5鈭3锛涳紙2锛塼an...
绛旓細鈭村潩搴曞AB=AF+EF+EB=5.4+2.5+4.53=7.9+4.53锛坢锛夛紟锛7鍒嗭級鐐硅瘎锛氭棰樹富瑕佽冩煡瀛︾敓瀵瑰潯搴﹀潯瑙掔殑鐞嗚В鍙姊舰鐨勬ц川鐨勮繍鐢ㄨ兘鍔涳紟
绛旓細瑙ｇ瓟锛氳В锛氾紙1锛夌敱棰樻剰寰桟E=DF=4.5锛宼anB=33锛屸埓BC=5绫筹紝BE=923m锛涳紙2锛塼an鈭燘=33锛屾晠鍙緱鍑築C鐨勫潯瑙掍负1锛3锛涳紙3锛夌敱AD鐨勫潯搴︿负1锛1.2鍙煡tan鈭燗=56锛屽張DF=4.5锛屸埓AF=5.4锛屸埓AB=AF+FE+EB=5.4+2.5+2.53=锛7.9+923锛夌背锛
绛旓細杩囩偣A鍋欰E鍨傜洿浜嶣C涓庣偣E,杩囩偣D鍋欴F鍨傜洿浜嶣C涓庣偣F,鍒欐按鍧妯埅闈绉=鐩磋涓夎褰BE+鐭╁舰AEFD+鐩磋涓夎褰FC 銆傚洜涓姊舰ABCD锛岃ADC涓135搴︼紝瑙扗CF=45搴︼紝鍙圖C涓8鏍瑰彿2绫筹紝鎵浠D=FC=8绫筹紝鐩磋涓夎褰FC 闈㈢Н=DF*FC/2=8*8/2=32骞虫柟绫筹紝鐭╁舰AEFD闈㈢Н=AD*DF=6*8=48骞虫柟绫,AB鐨勫潯搴︿负1姣...
绛旓細鍧濈殑鍦熸柟=鍧濈殑妯埅闈㈢殑闈㈢Н脳鍧濈殑闀垮害 璁惧潩鐨勯珮鏄x锛屽垯AE=x锛孊F=2x锛孉B=3+3x锛屼緷棰樻剰锛屽緱锛 2/1锛3+3+3x锛墄脳30=4500锛姊舰鐨勬í鎴潰鍏紡锛夋暣鐞嗭紝寰楋細x²+2x-100=0 瑙ｅ緱x=2/(-1卤鏍瑰彿101)鑸嶅幓x=2/(-1-鏍瑰彿101)鎵浠=2/(-1+鏍瑰彿101)鈮9.05锛坢锛
绛旓細瑙ｇ瓟锛氳В锛氾紙1锛変綔DG鈯B浜嶨锛屼綔EH鈯B浜嶩锛庘埖CD鈥朅B锛屸埓EH=DG=5绫筹紝鈭 DG/AG=1/1.2锛屸埓AG=6绫筹紝鈭礒H/FH=1/1.4 锛屸埓FH=7绫筹紝鈭碏A=FH+GH-AG=7+1-6=2锛堢背锛夆埓SADEF= 2鍒嗕箣1锛圗D+AF锛•EH=2鍒嗕箣1 锛1+2锛壝5=7.5锛堝钩鏂圭背锛塚=7.5脳4000=30000锛堢珛鏂圭背锛夛紱绛...
绛旓細璁惧鍔犲悗涓婅竟涓篴,杩庢按鍧D鐨勫潯瑙掍负30掳,楂樹负6锛岃儗姘村潯BC鐨勫潯搴︿负1:1,鍙煡AB=a+0.5+0.5*鏍瑰彿3/3,鍒檃=3.5-0.5*鏍瑰彿3/3,澧炲姞鍦熸柟閲=1/2*1000*0.5*锛3.5-0.5*鏍瑰彿3/3+4锛
绛旓細5h=20鈭磆=2锛庣瓟锛氭渤鐨勬繁搴︿负2绫筹紟锛2锛変綔EG鈯D锛孎H鈯D锛屽瀭瓒冲垎鍒负G銆丠鍒橢F=GH锛孍G=FH=2鐢眎1=1锛1.5鐭ワ紝HC=3锛 鐢眎2=1锛2鐭ワ紝DG=4锛涒埓EF=GH=DC-DG-HC=13-4-3=6鈭碨姊疎FCD=12锛6+13锛壝2=19鈭撮渶鎸栧湡鏂逛负锛19脳2000=38000绔嬫柟绫筹紟绛旓細闇鎸栧湡38000绔嬫柟绫筹紟
绛旓細濡傚浘,鏈変竴姘村簱澶у潩鐨妯埅闈㈡槸姊舰ABCD,AD鈥朆C,EF涓烘按搴撶殑姘撮潰,鐐笶鍦―C涓,鏌愯棰樺皬缁勫湪鑰佸笀鐨勫甫棰嗕笅鎯虫祴閲忔按鐨勬繁搴,浠栦滑娴嬪緱鑳屾按鍧B鐨勯暱涓12绫,杩庢按鍧′笂DE鐨勯暱涓2绫,鈭燘AD=135... 濡傚浘,鏈変竴姘村簱澶у潩鐨勬í鎴潰鏄褰BCD,AD鈥朆C,EF涓烘按搴撶殑姘撮潰,鐐笶鍦―C涓,鏌愯棰樺皬缁勫湪鑰佸笀鐨勫甫棰嗕笅鎯虫祴閲忔按鐨勬繁搴,...
