问题 填空题
在△ABC中,若
OA
OB
=
OB
OC
=
OC
OA
,那么点O是△ABC的______.(填:外心、内心、重心、垂心)
答案

OA
OB
=
OB
OC

OB
•(
OC
-
OA
)=
OB
AC
=0

即OB⊥AC

同理可证:OA⊥BC,OC⊥AB

故点O是△ABC的三条高的交点,

故点O是△ABC的垂心

故答案为:垂心

单项选择题
名词解释