△ABC的周长为18,BC为4,BC边上的中线AD把△ABC分成周长差为2的两个三角形,AB=()AC=()
2个回答

C△ABC = AB+BC+AC = 18

BC = 4

∴AB + AC = 14

∵AD是BC上的中线

∴BD = CD

∵C△ABD = AB+BD + AD

C△ACD = AC + CD + AD

∴|C△ABD -C△ACD | = |AB - AC | = 2

∴联立方程组有

1)AB + AC = 14

AB -AC = 2

2)AB + AC = 14

AC-AB=2

所以分别解得AB = 8,AC = 6 或AB = 6,AC = 8