已知四边形ABCD的三个顶点A(0,2),B(-1,-2),C(3,1),且BC=2AD,则顶点D的坐标为(  ) A.(2,72) B.(2,−12) C.(3,2) D.(1,3)

问题描述:

已知四边形ABCD的三个顶点A(0,2),B(-1,-2),C(3,1),且

BC
=2
AD
,则顶点D的坐标为(  )
A. (2,
7
2
)

B. (2,−
1
2
)

C. (3,2)
D. (1,3)

设顶点D的坐标为(x,y)

BC
=(4,3),
AD
=(x,y−2)

BC
=2
AD

2x=4
2y−4=3
x=2
y=
7
2

故选A