问题
填空题
已知△ABC中AC=4,AB=2若G为△ABC的重心,则
|
答案
∵△ABC中AC=4,AB=2
∴|
|=4,|AC
|=2AB
∵G为△ABC的重心,
∴
=AG
(1 3
+AC
)AB
又∵
=BC
-AC AB
∴
•AG
=BC
(1 3
+AC
)•(AB
-AC
)=AB
(1 3
2-AC
2)=AB
(16-4)=41 3
故答案为:4
已知△ABC中AC=4,AB=2若G为△ABC的重心,则
|
∵△ABC中AC=4,AB=2
∴|
|=4,|AC
|=2AB
∵G为△ABC的重心,
∴
=AG
(1 3
+AC
)AB
又∵
=BC
-AC AB
∴
•AG
=BC
(1 3
+AC
)•(AB
-AC
)=AB
(1 3
2-AC
2)=AB
(16-4)=41 3
故答案为:4