![](https://static.youtibao.com/asksite/comm/h5/images/m_q_title.png)
[单选题]
已知线段AB=100cm,点C在直线AB上,BC=80cm,D、E分别是AC、BC的中点,则DE的长是()
A.50cm或40cm
B.50cm
C.40cm
D.60cm
![](https://static.youtibao.com/asksite/comm/h5/images/m_q_a.png)
A、50cm或40cm
![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)
A.50cm或40cm
B.50cm
C.40cm
D.60cm
A、50cm或40cm
A.(4,2)
B.(5,2)
C.(5,3)
D.(6,2)
A.(4,2)
B.(5,2)
C.(6,2)
D.(5,3)
A.(﹣1,2)
B.(1,0)
C.(﹣1,0)
D.(1,2)
A.(-7,2)
B.(0,2)
C.(-2,2)
D.(2.5,2)
A.(-2,1)
B.(0,1)
C.(7,-1)
D.(2.5,0)