满分5 >
初中数学试题 >
如图,△ABC中,点D、E分别是AB、AC的中点,则下列结论:①BC=2DE;②...
如图,△ABC中,点D、E分别是AB、AC的中点,则下列结论:①BC=2DE;②△ADE∽△ABC;③
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443014_ST/0.png)
.其中正确的有( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443014_ST/images1.png)
A.3个
B.2个
C.1个
D.0个
考点分析:
相关试题推荐
如图,已知等边三角形ABC的边长为2,DE是它的中位线,则下面四个结论:
(1)DE=1;
(2)AB边上的高为
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443013_ST/0.png)
;
(3)△CDE∽△CAB;
(4)△CDE的面积与△CAB面积之比为1:4.
其中正确的有( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443013_ST/images1.png)
A.1个
B.2个
C.3个
D.4个
查看答案
如图,△ABC中,CD⊥AB于D,一定能确定△ABC为直角三角形的条件的个数是( )
①∠1=∠A;②
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443012_ST/0.png)
;③∠B+∠2=90°;④BC:AC:AB=3:4:5;⑤AC•BD=AD•CD.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443012_ST/images1.png)
A.1
B.2
C.3
D.4
查看答案
如图,Rt△ABC中,AB⊥AC,AB=3,AC=4,P是BC边上一点,作PE⊥AB于E,PD⊥AC于D,设BP=x,则PD+PE=( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443011_ST/images0.png)
A.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443011_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443011_ST/1.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443011_ST/2.png)
D.
查看答案
如果一个直角三角形的两条边长分别是6和8,另一个与它相似的直角三角形边长分别是3和4及x,那么x的值( )
A.只有1个
B.可以有2个
C.有2个以上,但有限
D.有无数个
查看答案
如图,在△ABC中,∠C=90°,D是AC上一点,DE⊥AB于点E,若AC=8,BC=6,DE=3,则AD的长为( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101712360044385/SYS201311031017123600443009_ST/images0.png)
A.3
B.4
C.5
D.6
查看答案