【！~急~！】已知三个边长分别为2 3 5的正方形如图所列,则图中阴影部分的面积为
\u5df2\u77e5\u4e09\u4e2a\u8fb9\u957f\u5206\u522b\u4e3a2\uff0c3\uff0c5\u7684\u6b63\u65b9\u5f62\u5982\u56fe\u6392\u5217\uff0c\u5219\u56fe\u4e2d\u9634\u5f71\u90e8\u5206\u9762\u79ef\u4e3a? (\u8981\u8be6\u7ec6\u8fc7\u7a0b\u7684\u54e6\uff09\u76f4\u89d2\u4e09\u89d2\u5f62\u4e0b\u8fb92\uff1a\uff082+3\uff09\uff1a\uff082+3+5\uff09=2:5:10\uff0c
\u2234\u4e09\u6761\u7ad6\u7ebf2t\u3002\uff1a5t\uff1a10t\uff0c
\u7531\u53f3\u8fb9\u4e00\u7ad6\u4e3a5\uff0c\u223410t=5\uff0ct=1/2\uff0c
\u4e2d\u95f4\u4e0b\u9762\u68af\u5f62\u4e0a\u5e95=2t=1\uff0c\u4e0b\u5e955t=2.5\uff0c
\u2234S\u9634=\uff082+0.5\uff09\u00d73\u00f72=3.75.
\u56fe\u4e2d\u5927\u76f4\u89d2\u4e09\u89d2\u5f62\u77ed\u76f4\u89d2\u8fb9\u4e0e\u957f\u76f4\u89d2\u8fb9\u7684\u6bd4\u4f8b5/10=1/2\uff0c\u6c42\u5f97\u5176\u4ed6\u4e24\u4e2a\u76f4\u89d2\u4e09\u89d2\u5f62\uff0c\u77ed\u8fb9\u5206\u522b\u4e3a1\u548c2.5\uff0c\u56fe\u4e2d\u9634\u5f71\u90e8\u5206\u4e3a\u68af\u5f62\uff0c\u4e0a\u5e950.5\u4e0b\u5e952\u9ad83\uff0c\u9634\u5f71\u90e8\u5206\u9762\u79ef=2.5*3/2=3.75
边长3的空白处为一个梯形 设短边为a，长边为b，a:5=2:(2+3+5) a=1
同理 b=2.5
则梯形面积为0.5*（1+2.5）*3*=5.25
则阴影面积为3*3-5.25=3.75
绛旓細杈归暱3鐨勭┖鐧藉涓轰竴涓褰 璁剧煭杈逛负a锛岄暱杈逛负b锛宎:5=2:(2+3+5) a=1 鍚岀悊 b=2.5 鍒欐褰㈤潰绉负0.5*锛1+2.5锛*3*=5.25 鍒欓槾褰遍潰绉负3*3-5.25=3.75
绛旓細4+鏍瑰彿5 AB+CD=2 AD=2 BC=涓夊垎涔嬩竴鏂杈归暱=鏍瑰彿5
绛旓細(3)鏍规嵁宸茬煡杈归暱, 鍙垎鍒眰鍑:FG = CG - CF = 0.5;HG = BG - BH = 1;(4)鍒╃敤鍕捐偂瀹氱悊,鍙眰寰:FH = (鈭3)/2;(5)闃村奖閮ㄥ垎,鍗斥柍FHG鐨勯潰绉负:S = (1/2)路FG路FH = (鈭3)/8;
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