北师大版八年级下册《第1章 三角形的证明》同步练习卷A（19）

1、北师大版八年级下册第1章 三角形的证明2014年同步练习卷a（19）一、选择题（共3小题，每小题3分，满分9分）1如图，o为abc内任意一点，odab，oeac，ofbc，若od=oe=of，连接oa，ob，oc，下列说法不一定正确的是（）abodbofboad=obfccoe=cofdad=ae显示解析2三角形abc的三条内角平分线为ae、bf、cg，下面的说法中正确的个数有（）abc的内角平分线上的点到三边距离相等三角形的三条内角平分线交于一点三角形的内角平分线位于三角形的内部三角形的任一内角平分线将三角形分成面积相等的两部分a1个b2个c3个d4个显示解析3如图，在rtabc中，abc=

2、90，ad平分bac，deab于e，则下列结论中错误的是（）abd+ed=bcbda平分edcca、d两点一定在线段ec的垂直平分线上dde平分adb显示解析二、填空题（共2小题，每小题3分，满分6分）4如图，abc的三边ab、bc、ca长分别为40、50、60其三条角平分线交于点o，则sabo：sbco：scao=显示解析5如图所示，rtabc中，cf是斜边ab上的高，角平分线bd交cf于点g，deab于点e，则下列结论：a=bcf；cd=cg；ad=bd；bc=be正确结论的序号显示解析三、解答题（共1小题，满分0分）6如图，abc的三条内角平分线相交于点o，过点o作oebc于e点，（1）

3、求证：bod=coe（2）如果ab=17，ac=8，bc=15，利用三角形内心性质及相关知识，求oe长 tgz7r4i30ka1dkaghn3xtkknbycudxqa7fhyi2chhi92tgkqcwa3ptgshls50clmtwn60eo8wgqv7xav2ohum32wgeauwydiawgmer4i30ka1dkaghn3xtkknbycudxqa7fhyi2chhi92tgkqcwa3ptgz7r4i30ka1dkagtgk tgz7r4i30ka1dkaghn3xtkknbycudxqa7fhyi2chhi92tgkqcwa3ptgshls50clmtwn60eo8wgqv7x

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