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試卷第=page22頁(yè),共=sectionpages22頁(yè)試卷第=page11頁(yè),共=sectionpages11頁(yè)中考數(shù)學(xué)幾何專項(xiàng)練習(xí):相似模型--平行線構(gòu)造“A、X”型相似三角形(基礎(chǔ)+培優(yōu))一、單選題1.如圖,點(diǎn)SKIPIF1<0分別在SKIPIF1<0的邊SKIPIF1<0上,且SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0的值是(

)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<02.如圖,在SKIPIF1<0中,F(xiàn)是SKIPIF1<0上一點(diǎn),SKIPIF1<0交SKIPIF1<0于點(diǎn)E,SKIPIF1<0的延長(zhǎng)線交SKIPIF1<0的延長(zhǎng)線于點(diǎn)G,SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0的長(zhǎng)為(

A.4 B.6 C.8 D.103.如圖,D、E分別是SKIPIF1<0的邊SKIPIF1<0上的點(diǎn),SKIPIF1<0,若SKIPIF1<0,則SKIPIF1<0的值為()

A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<04.如圖,在SKIPIF1<0中,SKIPIF1<0為SKIPIF1<0上一點(diǎn),連接SKIPIF1<0,SKIPIF1<0,且SKIPIF1<0與SKIPIF1<0相交于點(diǎn)SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0(

A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<05.如下圖,如果SKIPIF1<0,若SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0()A.6 B.8 C.9 D.106.如圖,在SKIPIF1<0中,SKIPIF1<0,D、E分別為SKIPIF1<0中點(diǎn),連接SKIPIF1<0相交于點(diǎn)F,點(diǎn)G在SKIPIF1<0上,且SKIPIF1<0,則四邊形SKIPIF1<0的面積為(

A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<07.如圖,在SKIPIF1<0中,點(diǎn)D、E為邊SKIPIF1<0的三等分點(diǎn),點(diǎn)F、G在邊SKIPIF1<0上,SKIPIF1<0,點(diǎn)H為SKIPIF1<0與SKIPIF1<0的交點(diǎn).若SKIPIF1<0,則SKIPIF1<0的長(zhǎng)為()

A.1 B.SKIPIF1<0 C.2 D.38.如圖SKIPIF1<0中,SKIPIF1<0,點(diǎn)D,E分別是邊SKIPIF1<0,SKIPIF1<0的中點(diǎn),點(diǎn)G,F(xiàn)在SKIPIF1<0邊上,四邊形SKIPIF1<0是正方形.若SKIPIF1<0,則SKIPIF1<0的長(zhǎng)為(

A.2cm B.SKIPIF1<0cm C.4cm D.8cm二、填空題9.如圖,在平行四邊形SKIPIF1<0中,E是線段SKIPIF1<0上一點(diǎn),連結(jié)SKIPIF1<0交于點(diǎn)F.若SKIPIF1<0,則SKIPIF1<0.

10.如圖,矩形SKIPIF1<0中,SKIPIF1<0,E是SKIPIF1<0上一點(diǎn),SKIPIF1<0與SKIPIF1<0交于點(diǎn)F.則SKIPIF1<0的長(zhǎng)為.11.如圖,在矩形SKIPIF1<0中,若SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0的長(zhǎng)為.12.如圖,SKIPIF1<0與SKIPIF1<0位似,位似中心為點(diǎn)O.已知SKIPIF1<0,若SKIPIF1<0的周長(zhǎng)等于4,則SKIPIF1<0的周長(zhǎng)等于.13.如圖,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0交于點(diǎn)E,若SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0的長(zhǎng)為.

14.如圖,在SKIPIF1<0中,點(diǎn)D,E分別在SKIPIF1<0上,若SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0的長(zhǎng)為.15.如圖,點(diǎn)F在平行四邊形SKIPIF1<0的邊上,延長(zhǎng)SKIPIF1<0交SKIPIF1<0的延長(zhǎng)線于點(diǎn)E,交SKIPIF1<0于點(diǎn)O,若SKIPIF1<0,則SKIPIF1<0=.16.如圖,在矩形SKIPIF1<0中,若SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0的長(zhǎng)為.17.如圖,在SKIPIF1<0中,D,E分別是邊SKIPIF1<0,SKIPIF1<0的中點(diǎn),SKIPIF1<0,SKIPIF1<0相交于點(diǎn)F,則SKIPIF1<0.18.如圖,在矩形SKIPIF1<0中,E、F分別為邊SKIPIF1<0的中點(diǎn),SKIPIF1<0與SKIPIF1<0分別交于點(diǎn)P、Q.已知SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0的長(zhǎng)為.19.如圖,點(diǎn)D、E是SKIPIF1<0邊SKIPIF1<0上的點(diǎn),SKIPIF1<0,連接SKIPIF1<0,交點(diǎn)為F,SKIPIF1<0,那么SKIPIF1<0的值是.20.如圖,△ABC是等腰三角形,AB=AC=3,BC=1.點(diǎn)D在AB邊上,點(diǎn)E在CB的延長(zhǎng)線上,已知AD=1,BE=1,連接ED并延長(zhǎng)交AC于點(diǎn)F,則線段AF的長(zhǎng)為.21.如圖,已知SKIPIF1<0,SKIPIF1<0,SKIPIF1<0是三個(gè)全等的等腰三角形,底邊SKIPIF1<0,SKIPIF1<0,SKIPIF1<0在同一直線上,且SKIPIF1<0,SKIPIF1<0,SKIPIF1<0分別交SKIPIF1<0,SKIPIF1<0,SKIPIF1<0于SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0的長(zhǎng)為.22.如圖,線段AB,AC是兩條繞點(diǎn)A可以自由旋轉(zhuǎn)的線段(但點(diǎn)A,B,C始終不在同一條直線上),已知AB=5,AC=7,點(diǎn)D,E分別是AB,BC的中點(diǎn),則四邊形BEFD面積的最大值是.23.如圖,SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0分別在邊SKIPIF1<0,SKIPIF1<0上,SKIPIF1<0,SKIPIF1<0相交于點(diǎn)SKIPIF1<0,SKIPIF1<0,點(diǎn)SKIPIF1<0為SKIPIF1<0中點(diǎn),則SKIPIF1<0的值是.

24.如圖,SKIPIF1<0是SKIPIF1<0的中線,點(diǎn)E在SKIPIF1<0上,SKIPIF1<0交SKIPIF1<0于點(diǎn)F.若SKIPIF1<0,則SKIPIF1<0.25.如圖所示,在SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0、SKIPIF1<0分別是SKIPIF1<0、SKIPIF1<0的中點(diǎn),動(dòng)點(diǎn)SKIPIF1<0在射線SKIPIF1<0上,SKIPIF1<0交SKIPIF1<0于SKIPIF1<0,SKIPIF1<0的平分線交SKIPIF1<0于SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0.

26.如圖矩形SKIPIF1<0中,SKIPIF1<0,點(diǎn)SKIPIF1<0分別在SKIPIF1<0邊上,且SKIPIF1<0,連SKIPIF1<0與SKIPIF1<0分別交于點(diǎn)SKIPIF1<0.則SKIPIF1<0.

27.如圖,在矩形SKIPIF1<0中,SKIPIF1<0,E,F(xiàn)分別為SKIPIF1<0,SKIPIF1<0邊的中點(diǎn).動(dòng)點(diǎn)P從點(diǎn)E出發(fā)沿SKIPIF1<0向點(diǎn)A運(yùn)動(dòng),同時(shí),動(dòng)點(diǎn)Q從點(diǎn)F出發(fā)沿SKIPIF1<0向點(diǎn)C運(yùn)動(dòng),連接SKIPIF1<0,過(guò)點(diǎn)B作SKIPIF1<0于點(diǎn)H,連接SKIPIF1<0.若點(diǎn)P的速度是點(diǎn)Q的速度的2倍,在點(diǎn)P從點(diǎn)E運(yùn)動(dòng)至點(diǎn)A的過(guò)程中,線段SKIPIF1<0長(zhǎng)度的最小值為.

28.如圖,SKIPIF1<0為矩形SKIPIF1<0的對(duì)角線,SKIPIF1<0平分SKIPIF1<0交SKIPIF1<0于點(diǎn)SKIPIF1<0,SKIPIF1<0為SKIPIF1<0邊的中點(diǎn),連接SKIPIF1<0分別交SKIPIF1<0,SKIPIF1<0于點(diǎn)SKIPIF1<0,SKIPIF1<0.若SKIPIF1<0,SKIPIF1<0,則線段SKIPIF1<0的長(zhǎng)為.

29.在SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0是SKIPIF1<0中點(diǎn),連接SKIPIF1<0,過(guò)點(diǎn)SKIPIF1<0作SKIPIF1<0交SKIPIF1<0于點(diǎn)SKIPIF1<0,則SKIPIF1<0.

30.如圖,在SKIPIF1<0中,SKIPIF1<0,延長(zhǎng)SKIPIF1<0到點(diǎn)D,SKIPIF1<0,點(diǎn)E是SKIPIF1<0的中點(diǎn),SKIPIF1<0交SKIPIF1<0于點(diǎn)F,則SKIPIF1<0的面積為.

三、解答題31.如圖,在SKIPIF1<0中,對(duì)角線SKIPIF1<0和SKIPIF1<0相交于點(diǎn)O,在SKIPIF1<0的延長(zhǎng)線上取一點(diǎn)E,連接SKIPIF1<0交SKIPIF1<0于點(diǎn)F,SKIPIF1<0,求SKIPIF1<0的長(zhǎng)度.

32.教材呈現(xiàn):如圖是華師版九年級(jí)上冊(cè)數(shù)學(xué)教材第78頁(yè)的部分內(nèi)容.例2如圖,在SKIPIF1<0中,SKIPIF1<0、SKIPIF1<0分別是邊SKIPIF1<0、SKIPIF1<0的中點(diǎn),SKIPIF1<0、SKIPIF1<0相交于點(diǎn)SKIPIF1<0.求證:SKIPIF1<0.證明:連接SKIPIF1<0.

請(qǐng)根據(jù)教材提示,結(jié)合圖①,寫(xiě)出完整的證明過(guò)程.證明:連接SKIPIF1<0.

結(jié)論應(yīng)用:(1)如圖②,在SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0、SKIPIF1<0分別是邊SKIPIF1<0、SKIPIF1<0的中點(diǎn),SKIPIF1<0、SKIPIF1<0相交于點(diǎn)SKIPIF1<0.若SKIPIF1<0,則SKIPIF1<0.(2)如圖③,在SKIPIF1<0中,SKIPIF1<0、SKIPIF1<0分別是邊SKIPIF1<0、SKIPIF1<0的中點(diǎn),SKIPIF1<0、SKIPIF1<0相交于點(diǎn)SKIPIF1<0.過(guò)點(diǎn)G作SKIPIF1<0交AB于點(diǎn)F,如果SKIPIF1<0的面積是9,那么SKIPIF1<0的面積是.33.已知:如圖,在SKIPIF1<0中,點(diǎn)SKIPIF1<0,SKIPIF1<0分別在SKIPIF1<0,SKIPIF1<0上,SKIPIF1<0,點(diǎn)SKIPIF1<0在邊SKIPIF1<0上,SKIPIF1<0,SKIPIF1<0與SKIPIF1<0相交于點(diǎn)SKIPIF1<0.

(1)求證:SKIPIF1<0.(2)當(dāng)點(diǎn)SKIPIF1<0為SKIPIF1<0的中點(diǎn)時(shí),求證:SKIPIF1<0.34.閱讀材料:三角形的三條中線必交于一點(diǎn),這個(gè)交點(diǎn)稱為三角形的重心.

(1)特例感知:如圖(1),已知邊長(zhǎng)為2的等邊SKIPIF1<0的重心為點(diǎn)SKIPIF1<0,則SKIPIF1<0的面積為_(kāi)_____;(2)性質(zhì)探究:如圖(2),已知SKIPIF1<0的重心為點(diǎn)SKIPIF1<0,對(duì)于任意形狀的SKIPIF1<0,SKIPIF1<0是不是定值,如果是,請(qǐng)求出定值為多少,如果不是,請(qǐng)說(shuō)明理由;(3)性質(zhì)應(yīng)用:如圖(3),在任意矩形SKIPIF1<0中,點(diǎn)SKIPIF1<0是SKIPIF1<0的中點(diǎn),連接SKIPIF1<0交對(duì)角線SKIPIF1<0于點(diǎn)SKIPIF1<0,SKIPIF1<0的值是不是定值,如果是,請(qǐng)求出定值為多少,如果不是,請(qǐng)說(shuō)明理由.35.如圖,SKIPIF1<0中,SKIPIF1<0為SKIPIF1<0邊上的高,SKIPIF1<0的平分線SKIPIF1<0分別交SKIPIF1<0于點(diǎn)F,E.

(1)求證:SKIPIF1<0;(2)若SKIPIF1<0,求SKIPIF1<0的面積;(3)若SKIPIF1<0,求SKIPIF1<0的值.36.如圖,在平行四邊形ABCD中,對(duì)角線AC,BD交于點(diǎn)O.M為AD中點(diǎn),連接CM交BD于點(diǎn)N,且ON=1(1)求證:SKIPIF1<0;(2)求BD的長(zhǎng),37.如圖,已知四邊形ABCD是平行四邊形,E、F是CD上的點(diǎn).(1)求證:△MEF∽△MBA;(2)若AF、BE分別是∠DAB,∠CBA的平分線,求證:DF=EC.38.如圖,在SKIPIF1<0中,點(diǎn)E在SKIPIF1<0上,SKIPIF1<0,SKIPIF1<0和SKIPIF1<0相交于點(diǎn)F,過(guò)點(diǎn)F作SKIPIF1<0,交SKIPIF1<0于點(diǎn)G.

(1)求SKIPIF1<0的值.(2)若SKIPIF1<0,①求證:SKIPIF1<0.②求證:SKIPIF1<0.39.如圖,菱形SKIPIF1<0的對(duì)角線SKIPIF1<0、SKIPIF1<0相交于點(diǎn)SKIPIF1<0,過(guò)點(diǎn)SKIPIF1<0作SKIPIF1<0,且SKIPIF1<0,連接SKIPIF1<0、SKIPIF1<0.(1)求證:四邊形SKIPIF1<0為矩形.(2)若菱形SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0,求SKIPIF1<0的長(zhǎng).40.在SKIPIF1<0中,點(diǎn)SKIPIF1<0,SKIPIF1<0分別在邊SKIPIF1<0,SKIPIF1<0上,連接SKIPIF1<0,SKIPIF1<0交于點(diǎn)SKIPIF1<0,且SKIPIF1<0,(1)求證:SKIPIF1<0:(2)當(dāng)SKIPIF1<0為邊SKIPIF1<0的中點(diǎn)時(shí),且SKIPIF1<0,①若SKIPIF1<0,求SKIPIF1<0;②若SKIPIF1<0為等腰直角三角形,且SKIPIF1<0,求四邊形SKIPIF1<0的面積.41.如圖,四邊形SKIPIF1<0為邊長(zhǎng)為8的正方形,點(diǎn)SKIPIF1<0為邊SKIPIF1<0中點(diǎn),SKIPIF1<0,SKIPIF1<0分別為邊SKIPIF1<0,SKIPIF1<0上兩動(dòng)點(diǎn),SKIPIF1<0于SKIPIF1<0.(1)求證:SKIPIF1<0;(2)若點(diǎn)SKIPIF1<0為SKIPIF1<0中點(diǎn),連接SKIPIF1<0并延長(zhǎng)交SKIPIF1<0于點(diǎn)SKIPIF1<0,求SKIPIF1<0的長(zhǎng).42.如圖,SKIPIF1<0中,點(diǎn)E是SKIPIF1<0的中點(diǎn),連接SKIPIF1<0并延長(zhǎng)交SKIPIF1<0的延長(zhǎng)線于點(diǎn)F.

(1)求證:SKIPIF1<0;(2)點(diǎn)G是線段SKIPIF1<0上一點(diǎn),滿足SKIPIF1<0,SKIPIF1<0交SKIPIF1<0于點(diǎn)H,若SKIPIF1<0,求SKIPIF1<0的長(zhǎng).43.如圖,在SKIPIF1<0中,SKIPIF1<0為SKIPIF1<0的中點(diǎn),SKIPIF1<0,SKIPIF1<0與SKIPIF1<0分別相交于點(diǎn)SKIPIF1<0,SKIPIF1<0.(1)求SKIPIF1<0的值;(2)若SKIPIF1<0,且SKIPIF1<0,SKIPIF1<0.求SKIPIF1<0的長(zhǎng).44.已知SKIPIF1<0是等邊三角形,SKIPIF1<0是直線SKIPIF1<0上的一點(diǎn).(1)問(wèn)題背景:如圖SKIPIF1<0,點(diǎn)SKIPIF1<0,SKIPIF1<0分別在邊SKIPIF1<0,SKIPIF1<0上,且SKIPIF1<0,SKIPIF1<0與SKIPIF1<0交于點(diǎn)SKIPIF1<0,求證:SKIPIF1<0;(2)點(diǎn)SKIPIF1<0,SKIPIF1<0分別在邊SKIPIF1<0,SKIPIF1<0上,SKIPIF1<0與SKIPIF1<0交于點(diǎn)SKIPIF1<0,且SKIPIF1<0.①嘗試運(yùn)用:如圖SKIPIF1<0,點(diǎn)SKIPIF1<0在邊SKIPIF1<0上,且SKIPIF1<0,求SKIPIF1<0的值;②類比拓展:如圖3,點(diǎn)SKIPIF1<0在SKIPIF1<0的延長(zhǎng)線上,且SKIPIF1<0,直接寫(xiě)出SKIPIF1<0的值.45.[基礎(chǔ)鞏固](1)如圖①,在SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0于點(diǎn)SKIPIF1<0,求證:SKIPIF1<0.[嘗試應(yīng)用](2)如圖②,在矩形SKIPIF1<0中,SKIPIF1<0,點(diǎn)SKIPIF1<0在SKIPIF1<0上,SKIPIF1<0,SKIPIF1<0于點(diǎn)SKIPIF1<0,求SKIPIF1<0的長(zhǎng).[拓展提高](3)如圖③,在矩形SKIPIF1<0中,點(diǎn)SKIPIF1<0在邊SKIPIF1<0上,SKIPIF1<0與SKIPIF1<0關(guān)于直線SKIPIF1<0對(duì)稱,點(diǎn)SKIPIF1<0的對(duì)稱點(diǎn)SKIPIF1<0在邊SKIPIF1<0上,SKIPIF1<0為SKIPIF1<0中點(diǎn),連接SKIPIF1<0交SKIPIF1<0于點(diǎn)SKIPIF1<0,SKIPIF1<0,若SKIPIF1<0,求SKIPIF1<0的長(zhǎng).46.如圖,矩形SKIPIF1<0的對(duì)角線SKIPIF1<0、SKIPIF1<0相交于點(diǎn)SKIPIF1<0,延長(zhǎng)SKIPIF1<0到點(diǎn)SKIPIF1<0,使SKIPIF1<0,連接SKIPIF1<0,連接SKIPIF1<0交SKIPIF1<0于點(diǎn)SKIPIF1<0,交SKIPIF1<0于點(diǎn)SKIPIF1<0.(1)求證:四邊形SKIPIF1<0是平行四邊形;(2)求證:SKIPIF1<0;(3)若SKIPIF1<0,SKIPIF1<0,求線段SKIPIF1<0的長(zhǎng)度.47.如圖,在SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0是線段SKIPIF1<0上的一點(diǎn),連接SKIPIF1<0,過(guò)點(diǎn)SKIPIF1<0作SKIPIF1<0,分別交SKIPIF1<0,SKIPIF1<0于點(diǎn)SKIPIF1<0,SKIPIF1<0,與過(guò)點(diǎn)A且垂直于SKIPIF1<0的直線相交于點(diǎn)SKIPIF1<0,連接SKIPIF1<0(1)求證:SKIPIF1<0(2)若SKIPIF1<0是SKIPIF1<0的中點(diǎn),求SKIPIF1<0的值.(3)若SKIPIF1<0,求SKIPIF1<0的值.48.【教材呈現(xiàn)】下圖是華師版九年級(jí)上冊(cè)數(shù)學(xué)教材64頁(yè)的部分內(nèi)容.如圖,在SKIPIF1<0中,D是邊SKIPIF1<0的四等分點(diǎn),SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0.求四邊形SKIPIF1<0的周長(zhǎng).問(wèn)題解決:請(qǐng)結(jié)合圖1給出解題過(guò)程.問(wèn)題探究(1)如圖2,在SKIPIF1<0中,D是邊SKIPIF1<0上的一點(diǎn),過(guò)點(diǎn)D作SKIPIF1<0,交SKIPIF1<0于點(diǎn)F,過(guò)點(diǎn)D作SKIPIF1<0,交SKIPIF1<0于點(diǎn)E,延長(zhǎng)SKIPIF1<0至H,使SKIPIF1<0,連接SKIPIF1<0交SKIPIF1<0于G.若SKIPIF1<0.SKIPIF1<0的面積為2,則SKIPIF1<0的面積為_(kāi)_____.(2)如圖3,在SKIPIF1<0中,D是邊SKIPIF1<0上的一點(diǎn),且SKIPIF1<0,連接SKIPIF1<0,E為SKIPIF1<0上一點(diǎn),連接SKIPIF1<0交SKIPIF1<0于點(diǎn)F,若F為SKIPIF1<0的中點(diǎn),SKIPIF1<0的面積為m,則SKIPIF1<0的面積為_(kāi)_____(含m的代數(shù)式表示).49.探究題:(1)特例感知:如圖①,在SKIPIF1<0中,SKIPIF1<0,點(diǎn)D是SKIPIF1<0邊上的中點(diǎn),SKIPIF1<0,交SKIPIF1<0的延長(zhǎng)線于點(diǎn)E,SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0度;SKIPIF1<0的長(zhǎng)為;(2)數(shù)學(xué)思考:如圖②,在SKIPIF1<0中,SKIPIF1<0,點(diǎn)D是SKIPIF1<0邊上的一點(diǎn),且SKIPIF1<0,SKIPIF1<0,交SKIPIF1<0的延長(zhǎng)線于點(diǎn)E,SKIPIF1<0,SKIPIF1<0.求SKIPIF1<0的度數(shù)和SKIPIF1<0的長(zhǎng).(3)拓展應(yīng)用:如圖③,在四邊形SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0,對(duì)角線SKIPIF1<0相交于點(diǎn)E,且SKIPIF1<0,SKIPIF1<0,SKIPIF1<0.求SKIPIF1<0的長(zhǎng).50.如圖1,在正方形SKIPIF1<0中,SKIPIF1<0是SKIPIF1<0上一點(diǎn),作SKIPIF1<0,垂足為點(diǎn)SKIPIF1<0,交SKIPIF1<0于點(diǎn)SKIPIF1<0.(1)求證:SKIPIF1<0;(2)如圖2,延長(zhǎng)SKIPIF1<0交SKIPIF1<0的延長(zhǎng)線于點(diǎn)SKIPIF1<0;①如果SKIPIF1<0是SKIPIF1<0的中點(diǎn),求SKIPIF1<0的值;②如果SKIPIF1<0,求SKIPIF1<0的長(zhǎng)度.51.如圖,矩形SKIPIF1<0中,SKIPIF1<0.SKIPIF1<0是邊SKIPIF1<0上一動(dòng)點(diǎn)(不與點(diǎn)SKIPIF1<0重合),延長(zhǎng)SKIPIF1<0到SKIPIF1<0,使SKIPIF1<0,SKIPIF1<0,SKIPIF1<0交于點(diǎn)SKIPIF1<0,連接SKIPIF1<0并延長(zhǎng)交SKIPIF1<0于點(diǎn)SKIPIF1<0.(1)若SKIPIF1<0,求證:SKIPIF1<0;(2)探究:當(dāng)點(diǎn)SKIPIF1<0運(yùn)動(dòng)時(shí),點(diǎn)SKIPIF1<0的位置是否發(fā)生變化?請(qǐng)說(shuō)明理由;52.已知SKIPIF1<0是等邊三角形,D是直線SKIPIF1<0上的一點(diǎn).(1)問(wèn)題背景:如圖1,點(diǎn)D,E分別在邊SKIPIF1<0,SKIPIF1<0上,且SKIPIF1<0,SKIPIF1<0與SKIPIF1<0交于點(diǎn)SKIPIF1<0,求證:SKIPIF1<0;(2)點(diǎn)G,H分別在邊SKIPIF1<0,SKIPIF1<0上,SKIPIF1<0與SKIPIF1<0交于點(diǎn)SKIPIF1<0,且SKIPIF1<0.①嘗試運(yùn)用:如圖2,點(diǎn)D在邊SKIPIF1<0上,且SKIPIF1<0,求SKIPIF1<0的值;②類比拓展:如圖3,點(diǎn)D在SKIPIF1<0的延長(zhǎng)線上,且SKIPIF1<0,直接寫(xiě)出SKIPIF1<0的值.53.綜合與探究(1)如圖1,在正方形SKIPIF1<0中,點(diǎn)E,F(xiàn)分別在邊SKIPIF1<0上,且SKIPIF1<0,則線段SKIPIF1<0與SKIPIF1<0的之間的數(shù)量關(guān)系為_(kāi)_____;(2)【類比探究】如圖2,在矩形SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0,點(diǎn)E,F(xiàn)分別在邊SKIPIF1<0上,且SKIPIF1<0,請(qǐng)寫(xiě)出線段SKIPIF1<0與SKIPIF1<0的數(shù)量關(guān)系,并證明你的結(jié)論.(3)【拓展延伸】如圖3,在SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,D為SKIPIF1<0上一點(diǎn),且SKIPIF1<0,連接SKIPIF1<0,過(guò)點(diǎn)B作SKIPIF1<0于點(diǎn)F,交SKIPIF1<0于點(diǎn)E,求SKIPIF1<0的長(zhǎng).54.【教材呈現(xiàn)】如圖是蘇科版版數(shù)學(xué)教材第86頁(yè)的部分內(nèi)容.猜想:如圖,在SKIPIF1<0中,點(diǎn)D、E分別是SKIPIF1<0與SKIPIF1<0的中點(diǎn),根據(jù)畫(huà)出的圖形,可以猜想:

SKIPIF1<0,且SKIPIF1<0.對(duì)此,我們可以用演繹推理給出證明.

(1)【定理證明】請(qǐng)根據(jù)教材內(nèi)容,結(jié)合圖①,寫(xiě)出證明過(guò)程.(2)【定理應(yīng)用】如圖②,四邊形SKIPIF1<0中,M、N、P分別為SKIPIF1<0的中點(diǎn),邊SKIPIF1<0延長(zhǎng)線交于點(diǎn)E,SKIPIF1<0,則SKIPIF1<0______.(3)如圖③,在SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0,E、F分別為SKIPIF1<0上一點(diǎn),M、N分別為SKIPIF1<0的中點(diǎn).當(dāng)SKIPIF1<0時(shí),SKIPIF1<0______.55.某數(shù)學(xué)興趣小組在數(shù)學(xué)課外活動(dòng)中,對(duì)多邊形內(nèi)兩條互相垂直的線段做了如下探究:【觀察與猜想】(1)如圖①,在正方形SKIPIF1<0中,點(diǎn)SKIPIF1<0,SKIPIF1<0分別是SKIPIF1<0、SKIPIF1<0上的兩點(diǎn),連接SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,求證SKIPIF1<0SKIPIF1<0.【類比探究】(2)如圖②,在矩形SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0,點(diǎn)SKIPIF1<0是邊SKIPIF1<0上一點(diǎn),連接SKIPIF1<0,SKIPIF1<0,且SKIPIF1<0,求SKIPIF1<0的值.【拓展延伸】(3)如圖③,在SKIPIF1<0中,SKIPIF1<0,點(diǎn)SKIPIF1<0在SKIPIF1<0邊上,連接SKIPIF1<0,過(guò)點(diǎn)SKIPIF1<0作SKIPIF1<0于點(diǎn)SKIPIF1<0,SKIPIF1<0的延長(zhǎng)線交SKIPIF1<0邊于點(diǎn)SKIPIF1<0若SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,求SKIPIF1<0的值.56.請(qǐng)閱讀下列材料,非完成相應(yīng)的任務(wù).利用輔助平行線求線段的比三角形的中位線定理是三角形的中位線平行于第三邊,且等于第三邊的一半.平行線分線段成比例定理是兩條平行線被兩條直線所截,截得的線段對(duì)應(yīng)成比例.有些幾何題,若題中出現(xiàn)了平行線,我們可以直接利用這兩個(gè)定理求出兩線段的比值,而有些幾何題,題中沒(méi)有平行線這樣的條件,那么我們可以通過(guò)作輔助平行線,然后再利用這兩個(gè)定理加以解決.舉例:如圖1,SKIPIF1<0是SKIPIF1<0的中線,SKIPIF1<0,SKIPIF1<0的延長(zhǎng)線交SKIPIF1<0于點(diǎn)F.求SKIPIF1<0的值.下面是該題的部分解題過(guò)程:解:如圖2,過(guò)點(diǎn)D作SKIPIF1<0交SKIPIF1<0于點(diǎn)H.∵SKIPIF1<0是SKIPIF1<0的中線,∴SKIPIF1<0.∵SKIPIF1<0,∴SKIPIF1<0,∴SKIPIF1<0.∵SKIPIF1<0,…

任務(wù):(1)請(qǐng)補(bǔ)充材料中剩余部分的解答過(guò)程.(2)上述解題過(guò)程主要用的數(shù)學(xué)思想是______.(單選)A.方程思想

B.轉(zhuǎn)化思想

C.分類思想

D.整體思想(3)請(qǐng)你換一種思路求SKIPIF1<0的值,直接寫(xiě)出輔助線的作法即可.57.如圖①在SKIPIF1<0SKIPIF1<0中;SKIPIF1<0、SKIPIF1<0分別是邊SKIPIF1<0、SKIPIF1<0的中點(diǎn),SKIPIF1<0、SKIPIF1<0相交于點(diǎn)SKIPIF1<0.

(1)結(jié)論應(yīng)用:連接SKIPIF1<0,結(jié)合圖①,求證:SKIPIF1<0.(2)在平行四邊形SKIPIF1<0中,對(duì)角線SKIPIF1<0、SKIPIF1<0交于點(diǎn)SKIPIF1<0,SKIPIF1

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