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
=2BC
,则顶点D的坐标为( )AD
A. (2,
)7 2
B. (2,−
)1 2
C. (3,2)
D. (1,3)
答
设顶点D的坐标为(x,y)
∵
=(4,3),BC
=(x,y−2),AD
且
=2BC
,AD
∴
⇒
2x=4 2y−4=3
x=2 y=
7 2
故选A