如图, AM=1/3AB, AN=1/3AC.求证:MN=1/3BC.
问题描述:
如图,
=AM
1 3
, AB
=AN
1 3
.求证:AC
=MN
1 3
.BC
答
证明:∵
=AM
1 3
, AB
=AN
1 3
,AC
∴
=MN
-AN
=AM
(1 3
-AC
)=AB
1 3
.BC