如图,△ABC中,E、D是BC边上的三等分点,F是AC的中点,BF交AD、AE于G,H,试求BG:GH:HF

2025-01-21 09:23:02
推荐回答(1个)
回答1:

过F作FN BC,交AE于M,AD于N,
∵F为AC中点,
∴FM是△AEC中位线,
∴MF=
1
2
CE,CE=2FM,
∵BD=DE=CE,
∴BE=2CE=4FM,
∵FM BC,
∴△FMH △BEH,
FH
BH
=
FM
BE
=
1
4

∵FN是△ADC的中位线,
∴FN=
1
2
CD=CE=BD,
∵FN BC,
∴△FNG △BDG,
BG
GF
=
BD
FN
=
1
1

∴BG=GF,
FH
BH
=
1
4

FH
BF
=
1
5

∴FH=
1
5
BF,
∵BG=
1
2
BF,HF=
1
5
BF,
∴GH=GF-HF=
1
2
BF-
1
5
BF=
3
10
BF,
∴BG:GH:HF=(
1
2
BF):(
3
10
BF):(
1
5
BF)=5:3:2.