在如图所示的方格纸中,每个小正方形的边长为1,每个小正方形的顶点都叫做格点,已知点A、B、C都在格点上.
(1)按下列要求画图:过点B和一格点D画AC的平行线BD,过点C和一格点E画BC的垂线CE,并在图中标出格点D和E;
(2)求三角形ABC的面积.
(1)按下列要求画图:过点B和一格点D画AC的平行线BD,过点C和一格点E画BC的垂线CE,并在图中标出格点D和E;
(2)求三角形ABC的面积.
![](https://img.xkw.com/dksih/QBM/2019/2/20/2144697392005120/2145692382855168/STEM/de4e349351354d699a460847621c6684.png?resizew=183)
17-18七年级·江苏苏州·期末 查看更多[7]
更新时间:2019-02-21 22:45:14
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【知识点】 根据平行线判定与性质证明
相似题推荐
解答题-证明题
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名校
【推荐1】【操作发现】如图①,剪两张对边平行的纸条,随意交叉叠放在一起,使重合的部分构成一个四边形
.转动其中一张纸条,发现四边形
总是平行四边形其中判定的依据是__________.
【探究提升】取两张短边长度相等的平行四边形纸条
和
(
,
),其中
,
,将它们按图②放置,
落在边
上,
与边
分别交于点M,N.求证:
是菱形.
【结论应用】保持图②中的平行四边形纸条
不动,将平行四边形纸条
沿
或
平移,且
始终在边
上.当
时,延长
交于点P,得到图③.若四边形
的周长为40,
(
为锐角),则四边形
的面积为_________.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aba63d391602d0798a1875da35fef40d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aba63d391602d0798a1875da35fef40d.png)
【探究提升】取两张短边长度相等的平行四边形纸条
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d09a9a6f020159406608000cf93d4fa9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db976d8a85afef0166c5930d945ac177.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d163ba9cef35eb600387bcfbbda89ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2ab7ea8e7a0dc8c9f0b3a96a62c0eab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb47627049fdbc2ef8dcc8fbb8e32fc7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d830f2d923a554640d1d80abf3020606.png)
【结论应用】保持图②中的平行四边形纸条
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc0e8294c711a21ba01500869e6b122c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/259e274a370494eb7ad40074a14f9882.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/899df556f311b68eb9d57e2e938ff3b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f34dec1d0edf187e7677ecf9218e4a81.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20ca0ea573af39647bbb44977ed1eeb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/899df556f311b68eb9d57e2e938ff3b0.png)
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【推荐2】说出下列命题的逆命题,并判断每对命题的真假:
(1)四边形是多边形;
(2)两直线平行,同旁内角互补;
(3)如果
,那么
.
(1)四边形是多边形;
(2)两直线平行,同旁内角互补;
(3)如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3019b662e5dc2750bb6f9199d3250f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c7fb705ce2fe854e6a47558ca5d2580.png)
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