Question

知线段AB，延长到AB到C，使BC=二分之一AB，延长BA到D，使AD=2AB，M,N分别是BC，AD的中点，若MN=18cm求AB长

Answer 1

AB=NM-NA-BM
=MN-AD/2-BC/2
=18-2AB/2-0.5AB/2
=18-AB-AB/4

AB+AB+AB/4=18
4AB+4AB+AB=18x4
AB=18x4/9=8(cm)

追问

求图中所有线段的和.

追答

所有线段的和=DN+NA+AB+BM+MC
=DA+AB+BC
=AD+AB+BC
=2AB+AB+0.5AB
=3.5AB
=3.5x8
=28(cm);