资源描述
,正方形对角线的性质,人教,版 八,年级下,第十八章 平行四边形,18.2.5,1,2,3,4,5,C,6,7,22,答 案 呈 现,温馨,提示,:,点击,进入,讲评,习题链接,B,【2020,包头,】,如图,在正方形,ABCD,中,,E,是对角线,BD,上一点,,AE,的延长线交,CD,于点,F,,连接,CE,.,若,BAE,56,,则,CEF,_.,1,22,【2020,枣庄,】,如图,,E,,,F,是正方形,ABCD,的对角线,AC,上的两点,,AC,8,,,AE,CF,2,,则四边形,BEDF,的周长是,_,2,【2021,重庆,】,如图,正方形,ABCD,的对角线,AC,,,BD,交于点,O,,,M,是边,AD,上一点,连接,OM,,过点,O,作,ON,OM,,交,CD,于点,N,.,若四边形,MOND,的面积是,1,,则,AB,的长为,(,),3,C,【点拨】,四边形,ABCD,是正方形,,MDO,NCO,45,,,OD,OC,,,DOC,90.,DON,CON,90.,ON,OM,,,MON,90.,DON,DOM,90.,DOM,CON,.,DOC,的面积是,1.,正方形,ABCD,的面积是,4,,,即,AB,:,2,4.,AB,2.,【,中考,宜昌,】,如图,正方形,ABCD,的边长为,1,,点,E,,,F,分别是对角线,AC,上的两点,,EG,AB,,,EI,AD,,,FH,AB,,,FJ,AD,,垂足分别为,G,,,I,,,H,,,J,,则图中阴影部分的面积等于,(,),4,B,5,【2021,铜仁,】,如图,将边长为,1,的正方形,ABCD,绕点,A,顺时针旋转,30,到,AB,1,C,1,D,1,的位置,则阴影部分的面积是,_,6,【2021,绍阳,】,如图,在正方形,ABCD,中,对角线,AC,,,BD,相交于点,O,,点,E,,,F,是对角线,AC,上的两点,,且,AE,CF,.,连接,DE,,,DF,,,BE,,,BF,.,(1),求证,ADE,CBF,;,【2020,武威,】,如图,点,M,,,N,分别在正方形,ABCD,的边,BC,,,CD,上,且,MAN,45.,把,ADN,绕点,A,顺时针旋转,90,得到,ABE,.,(1),求证,AEM,ANM,;,7,证明:把,ADN,绕点,A,顺时针旋转,90,得到,ABE,,,ADN,ABE,.,DAN,BAE,,,DN,BE,,,AN,AE,.,由题易知,E,在,CB,的延长线上,DAB,90,,,MAN,45,,,MAE,BAE,BAM,DAN,BAM,45,.,MAE,MAN,.,又,MA,MA,,,AE,AN,,,AEM,ANM,(SAS),(2),若,BM,3,,,DN,2,,求正方形,ABCD,的边长,解:设,CD,BC,x,,则,CM,x,3,,,CN,x,2.,AEM,ANM,,,EM,MN,.,BE,DN,,,MN,EM,BM,BE,BM,DN,5.,C,90,,,MN,2,CM,2,CN,2,,即,5,2,(,x,3),2,(,x,2),2,.,化简,得,x,2,5,x,6,0.,因式分解,得,(,x,6)(,x,1),0.,故,x,6,0,或,x,1,0,,,解得,x,6,或,x,1(,舍去,),正方形,ABCD,的边长为,6.,
展开阅读全文