满分5 >
初中数学试题 >
已知⊙O是△ABC的外接圆,若AB=AC=5,BC=6,则⊙O的半径为( ) A...
已知⊙O是△ABC的外接圆,若AB=AC=5,BC=6,则⊙O的半径为( )
A.4
B.3.25
C.3.125
D.2.25
考点分析:
相关试题推荐
如图,⊙O是△ABC的外接圆,已知∠B=60°,则∠CAO的度数是( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908820858/SYS201311031016309088208002_ST/images0.png)
A.15°
B.30°
C.45°
D.60°
查看答案
如图,△ABC是⊙O的内接三角形,AD⊥BC于D点,且AC=5,CD=3,AB=4
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908820858/SYS201311031016309088208001_ST/0.png)
,则⊙O的直径等于( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908820858/SYS201311031016309088208001_ST/images1.png)
A.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908820858/SYS201311031016309088208001_ST/1.png)
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908820858/SYS201311031016309088208001_ST/2.png)
B.3
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908820858/SYS201311031016309088208001_ST/3.png)
C.5
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908820858/SYS201311031016309088208001_ST/4.png)
D.7
查看答案
有下列四个命题:①直径是弦;②经过三个点一定可以作圆;③三角形的外心到三角形各顶点的距离都相等;④半径相等的两个半圆是等弧.其中正确的有( )
A.4个
B.3个
C.2个
D.1个
查看答案
如图所示,甲、乙、丙三个三角形,每个三角形的内角均为55°、60°、65°.若
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908708785/SYS201311031016309087087029_ST/0.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908708785/SYS201311031016309087087029_ST/1.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908708785/SYS201311031016309087087029_ST/2.png)
,则甲、乙、丙周长的关系为( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908708785/SYS201311031016309087087029_ST/images3.png)
A.甲=乙=丙
B.甲<乙<丙
C.甲<丙<乙
D.丙<乙<甲
查看答案
小明不慎把家里的圆形玻璃打碎了,其中四块碎片如图所示,为配到与原来大小一样的圆形玻璃,小明带到商店去的一块玻璃碎片应该是( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101630908708785/SYS201311031016309087087028_ST/images0.png)
A.第①块
B.第②块
C.第③块
D.第④块
查看答案