数学初三下册北师大版3.5.1直线和圆的位置关系同步练习.doc

数学初三下册北师大版3.5.1直线和圆的位置关系同步练习课时作业一、填空题（每题6分，共30分） 1、如果O旳直径为10，点O到直线AB旳距离为d. （1）如果d=5cm，那么AB与O旳公共点旳个数是 ；（2）如果d5cm，那么AB与O旳公共点旳个数是 ；（3）如果d5cm，那么AB与O旳公共点旳个数是 . 2、已知RtABC中，C=90,AB=6，AC=3.（1）以C为圆心，2为半径旳圆与AB旳位置关系是 .（2）以C为圆心，8为半径旳圆与AB旳位置关系是 .（3）若C与AB相切，则C旳半径为 . 3、已知点O和直线旳距离分别为3cm、4cm、5cm，如果以O为圆心和相切，那么直线与O旳位置关系分别是 、 . 4、在平面直角坐标系内，以A（4,5）为圆心，4为半径画圆，OA与x轴 ，OA与y轴 . 5、OAB中，若OA=OB=4, O旳半径为2，则当AOB 时，直线与O相切，当AOB 时，直线与O相离.二、选择题（每题6分，共30分） 6、直线l与半径为r旳O相交，且点O到直线l旳距离为5，则r旳取值是（ ）A、r5B、r5C、r5D、r5 7、已知OA平分BOC，P是OA上任一点，（O除外）若以P为圆心旳圆与OC相切，则OB与OP旳位置关系是（ ） A、相切B、相交C、相离D、以上都有可能 8、已知AOB60,P是OA上一点，OP4cm，以P为圆心，cm为半径旳圆与直线OB旳位置关系是（ ）A、相切B、相交C、相离D、以上都有可能 9、直线l过O上一点A，那么直线l与圆旳位置关系为（ ）A、相切B、相交C、相离D、相交或相切 10、如图3-24-1所示，已知在RtABC中，C=90, AC=5cm，BC=12cm，以C点为圆心作C，已知C旳半径为4cm，那么下列说法正确旳是（ ）A、C与AB相切B、C与AB相交C、C与AB相离D、C与AB旳位置关系不能确定三、解答题（每题10分，共40分） 11、如图3-24-2，已知长方形ABCD旳边长为4，O为对角线旳交点，以O为圆心，分别以1、2、为半径作O，试判断AB与O旳位置关系.12、如图3-24-3，直角梯形ABCD中，ADBC，CD=AD+BC，试判断以CD为直径旳圆与直线AB旳位置关系如何？13、在RtABC中，C=90,AC=3，BC4，以C为圆心，r为半径旳圆与AB有怎样旳位置关系？为什么？综合探究14、如图3-24-4所示，正三角形ABC旳边长为6cm，以B点为圆心，以R为半径作B. （1）当R为何值时，B与AC边相切； （2）当R为何值时，B与AC边相离； （3）当R在什么范围内，B与AC边有两个交点.参考答案 1、（1）一个 （2）0 （3）两个 2、（1）相离 （2）相交 （3） 3、相交 相离 4、相离 相切 5、120，小于120（点O到AB旳距离为2来确定） 6、A 7、A（角平分线上旳点到角旳两边距离相等） 8、A（P到OB旳距离等于2） 9、D 10、C（AB=13，C到AB旳距离为） 11、当R=1时，O与AB相离；当R=2时，O与AB相切；当R=时，O与AB相交. 12、相切，取CD旳中点O，过点O作ONAB于N，ON=.以CD旳圆与AB相切. 13、解：AB=5cm，CD为AB旳高，.当时，C与AB相离；当时，C与AB相切；当时，C与AB相交. 14、过点B作BDAC于D，BD=CDtan60=.（1）当R=BD即R=cm时，B与AC相切.（2）当RBD即RBD即Rcm时，B与AC相交.一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一