tren doan thang AC co do dai 12 cm ,lay diem B sao cho AB=5 cm .a, tinh do dai cua doan thang BC.b,goi M,N lan luot la trung diem cua doan thang AB ,BC . tinh do dai doan thang MN.c, lay diem D thuoc tia doi cua tia CA sao cho CD =7 cm . chung to rang diem C la trung diem cua doan thang BD

cho doan thang ab co do dai =60.goi c la tia doi cua ab sao cho ca=ab goi m la trung diem cua doan ac goi m la trung diem cua doan thang mb .tinh doan thang mn

Cho doan thang AB dai 8cm va mot diem C thuoc doan thang AB.Biet AC=4cm.

a)Diem C co phai la trung diem cua doan thang AB khong?Vi sao?

b)Goi D la trung diem cua doan thang AC.Tinh do dai doan thang BD.

Cho doan thang AB =8cm . Tren tia AB lay diem M sao cho AM=3cm 

a)Tinh do dai doan thang BM 

b)Goi N la trung diem cua doan thang BM . tinh do dai doan thang MN

c)Lay diem P htuoc tia doi cua tia AB sao cho MP=6cm . Hoi A co la trung diem cua doan thang MP ko ?vi sao

cho doan thang AB co do dai la a.goi C la diem thuoc tia doi cua tia AB.goi M la trung diem cua doan thang AC.goi N la trung diem cua doan  thang CB.

a)vi sao A nam giua C vaB

b)vi sao NB=CB:2

c)tinh do dai doan thang MN

cho 1 doan thang AB co do dai bang 1cm

goi A₁la trung diem cua doan thang AB

     A₂la trung diem cua doan thang A₁B

    A₃ la trung diem cua doan thang A₂B

...........................................................

tinh do dai doan thang AA₈

doan thang ab dai 6 cm .M la trung diem cua doan thang ab N la trung diem cua doan thang AM Tinh do dai doan thang NB

Do dai doan thang ANla

cho doan thang ab=6cm diem m thuoc doan thang ab biet bm =2cm

a tinh do dai doan thang am

b tten tia doi cua tia áb lay diem d sao cho ad=4cm tinh do dai doan thangDM

c diem A co phai la trung diem cua doan thang DM

Tren doan thang AC dai 12cm lay diem B  sao cho AB = 5cm

a) Tinh do dai cua doan thang BC

b) Goi MN lan luot la trung diem cua cac doan thang AB, AC.Tinh do dai doan thang MN

c) Lay D thuoc tia doi cua tia CA sao cho CD = 7cm.CTR diem C la trung diem cua doan thang BC